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19th JULY 1935

Involving  Driver J. Rugman and his Fireman W. Ayers,

extracted & adapted from the report by 

G.R.S. WILSON, Major 

On the 19th July between Streatham Common and Balham Stations on the Southern Railway a accident which occurred at 

about 8.09 p-m. involving the 5.18 p.m. train from Brighton (7.05 p.m. from East Grinstead) to Victoria was travelling at high 

speed on the up main line, when the coupled wheels of the engine became derailed. Fortunately no further derailment ensued, 

and there were no complaints of injury or shock from passengers or staff.

The train comprised the bogie coaches weighing 86 tons; it was drawn by tank engine No.2075, Class I.3 super-heater 4-4-2 

type, running bunker first, and weighing in working order 76 tons. The engine was fitted with the Westinghouse and brake 

operating blocks on the coupled wheels only, controlled by the ejector working the vacuum brake on all wheels of the train.

After a few seconds preliminary rolling, apparently unusual at this place, the coupled wheels of the engine left the rails to the 

left or cess side in quick succession; the train was then brought safely to a stand in about 540 yards, and the adjacent down 

main line was not fouled. The 18 passengers were de-trained and completed their journey by road transport, all being cleared 

by 9 p.m.

The engine suffered minor damage only, and after re-railment at 11 p.m., was able to work the stock to the depot at Stewart’s 

Lane. Damage to permanent way was confined to chairs, keys and fish-bolts, 423 chairs being bro en, 408 on the cess side and 

15 only on the six-foot side.

The weather was fine, and had been warm and dry for several days.

1. From East Croydon, the last stop before the derailment, the line runs in a northerly direction for about 1/2-mile to Windmill 

Bridge Junction, where the Clapham Junction and Victoria line diverges to the left from the line to London Bridge; thence it 

continues for a proximately 3 miles via Selhurst, Thornton Heath, K o r b q , and Streatham Common Stations to Streatham 

North Junction, where the Mitcham line converges from the west; the point of derailment is about 370 yards, and Balham 

Junction about 1 1/2 miles further on. The line has four tracks, the up and down main being on the west side, so that the up 

main, on which the train was running, is next to the cess.

Approaching Streatham Common Station, gradients are falling generally for 3 miles at 1 in 264 to 1 in 100; thereafter through 

this station the line rises at 1 in 880to 1 in 284 for 3/4 mile, after which it becomes undulating about the site of the derailment, 

north of which to Balham Junction, gradients are falling at l in 264, and level.

2. Permanent speed restrictions on the up main line are :-

40 m.p.h. through Windmill Bride Junction. 

60 m.p.h. through Streatham North Junction 

50 m.p.h. through Balham Junction.

At the two latter points the restriction is in force on account of the nmssarily modified superelevation through the connections. 

These speed restrictions are included in a special publioa tion which mvers the whole of t!e Southern Railway system, and is 

issued to all the staff concerned.

There are no speed restriction boards

3 At the site of the accident the line runs in cutting with retaining walls of varying height. Through the trailing connection of 

Streatham North Junction the up main fine is on a right-handed curve of 40 chains radius; 217 yards further on curvature is 

again right-handed at 60 chains radius, but on1 for a length of 50 yards. The intervening 217 yards is occupied by leaving and 

entering transitions separated by a 50 yard length of tangent under Mitcham Lane Bridge. Derailment took place on the 67 yard 

length of transition immediately following the short 60 chain right-handed curve; beyond this point curvature reverses ta left-

handed, again via transition, at radii of 60 to 75 chains.

For 60 m.p.h. the superelevation prescribed by the Company's standard rule (85 per cent. of the theoretical) for a 40 chain 

curve is 4 1/2 inches and for a 60 chain curve 3 ins. In this locality however, on account of the junction and the succession of 

short curves of varying radii, it has not been found possible to adhere to the rule. 

At the “ V “ crossing (1in18) of the trailing points of Streatham North Junction superelevation is therefore only 1 1/4 ins., rising 

through the lead to 2 ins. at the toe of the switch; thence on the 40 chain curve it varies from 28 ins, to 2 1/4 ins., but owing, 

probably, to vicissitudes of maintenance the run out now commences on the circular curve before the transition is reached, the 

greatest variation occurring here. viz., a drop from 2 ins, to 1 1/2 ins. in 30 ft., or 1/720. On the intervening length between the 

two circular curves superelevation varies from 1 1/2 ins to 1 7/8ins. for the first 85 yards: it then rises partly on the tangent 

portion, with minor variations. to 2 3/4 ins. on the short 60 chain curve, running out with good regularity at 1/720 on the 

transition curve where derailment took place; at the actual point of derailment superelevation was 1 1/2ins., and gauge 3/16in. 


The permanent way was relaid in 1926 with 95 Ibs. R.B.S.material, the 45-foot rails being carried in chairs weighing 46 lbs. 

each, secured b three coach screws each to 10 ins. by 5 ins. creosoted pine sleepers, 18 per rail length, at standard spacing; the 

4-bolt fishplates weight 32 1/4Ibs. per pair. 

Formation is clay and loam, and since the cutting was drained 6 or 7 years ago there has been no trouble from wet or soft 

foundation. To ballast is Meldon granite, but this does not extend below the underside of the sleepers, which mainly rest on 

older “ pebbly “ ballast; no extensive lifting has been carried out over this section in recent years but I understand that lifting 

on to Meldon ballast is now in hand, as art of s.rear program, other sections of the main line already received attention.

This is the main line between Brighton and the South Cost Towns and Victoria, and carries exceptionally heavy electric and 

steam traffic ; it is, therefore, placed in the highest class for maintenance purposes. The permanent may appeared to h in good 

condition; for about 400 yards in rear of the point of derailment, gauge varied from 3/16 in. tight to 3/16 in, slack, the greatest 

variation in one rail length being from 1/8 in. tight to 1/3 in. slack; sleepers were sound, and fastenings appeared to be holding 

well, although there was in places slight movement under traffic between chairs and sleepers. Line and level appeared to the eye 

to be very good, and noted that, there was no undue movement of sleepers on their bed under the passage of several trains, 

both electric and steam, at speeds in the neighbourhood of 60 miles per hour. although some sleepers appeared to be rather 

heavily packed at the ends, resulting in appreciable deflection under load.

5 The markings on the rail indicated clearly the sequence of derailment; 5 ft. 8 in. beyond be joint immediately preceding 

derailment a faint abrasion for a length of 7 ft. 5 in. along the running edge of the high (cess) rail was observed, after which 

there was e flange mark 19 f t . 11 in. long, the first derailed wheel thus dropping to the outside 33ft. forward of the joint. A 

bruise was found on the end of the next rail at about the centre of the head, followed by a flange mark somewhat deeper than the 

first, crossing to the outside of the rail in 9 ft, where the second wheel dropped over into the cess. It is therefore probable that 

the right trailing coupled wheel (left leading as running) was first derailed; it broke the fishbolts of the next joint. and the three 

preceding chairs, allowing the rail to give way outwards under the side pressure of the following driving wheel, the flange of 

which evidently struck the end of the next. rail, still more or less in its correct lateral position: once the flange was thus lifted to 

the head of the rail, derailment of the second wheel followed. It is possible that if the joint had not been released by the 

breakage of the fishbolts. the driving wheels would have kept to the rails. There was a second and smaller bruise on the rail end 

at the corner formed by the running edge and the end of the. rail, which was probably due to being struck by a following flange 

either of the engine bogie or of the train, fortunate without further derailment. If this following flange had struck the end of the 

rail more squarely the results might well have been serious.

In spite of careful search no object. which might have caused derailment. by obstruction was found on the permanent way.

6. Tank engine No.2075. - This (I.3) class of engine has a length over buffers of 40 ft. 11in., and a total length of wheel base of 

31 Ft. 2 in. The spacing between the axles of the leading bogie is 6 ft. 3 in., between he bogie centre and the driving axle 10 ft. 8 

in., between the coupled axles 8 ft. 9 in., and between the trailing coupled axle and the trailing pony axles ft. 6 in. The diameter 

of the coupled wheels is 6 ft 7 1/2 in., of the bogie wheels 3 ft. 6in., and of the trailing wheels 4 ft. 0 in. The designed fully 

loaded weights carried by the bogie: the driving and trailing coupled axles and the pony, are 21 tons 5 cwts.,19 tons 5 cwts.. 18 

tons 15 cwts., and 16 tons 15 cm &. respectively. The engine carries in the two side tanks and rear tank 2,110 gallons of water 

and in the bunker 3 tons of coal. The designed centre of gravity of the engine fully loaded is 5 ft.. fl in. above rail level and at 

the time of derailment it was approximately 4 ft. 8 in.; its longitudinal position with the engine fully loaded is 2 ft,.11 1/2in. 

forward of the centre of the driving axle.

The leading bogie is swing-link controlled, the setting of links being so arranged that the displacement of the bogie causes the 

whole engine to take a slight  heel towards the inside of a, curve; it has a total side movement. including axle box clearance, of 

2. 5/16; in. each way ; axle box clearances of the coupled axles are 1/16in,. and of the pony axle 1/8 in. each way; the main 

pony casting has a side movement each way of 2 3/4 in. controlled by a single coil spring, initially with a force of 1ton 1 cwt.. 

increasing to 2 tons 1cwts. at full travel. With regard to carrying springs, the bogie axle boxes each have two vertical coil 

springs, but all Four springs of the driving and trailing coupled wheels are laminated, each consisting of 13 plates 5 in. broad. 

3 being 5/8 in. and 10 1/2 in. thick; the pony bearing springs are also laminated, with 13 plates 5 in. broad, one being 3/4in: 

and 12 1/2 in. thick.

There: are: two inside cylinders I9 in. bore by 26 in. stroke, horizontally set,, with the right.-hand crank leading, and piston-

valves, operated by Stephenson’s link motion, the working pressure being 180 Ibs. per square inch.

Of the 27 engines in this class, all built for the former L.B. & S.C.R.. the first, No. 21, was constructed at Brighton Works in 

1907. It was virtually one of the 4-4-0 tender engines (Class B.4) built as a  tank engine by the extension of the frames at the 

trailing end to carry the bunker over a pair of pony truck wheels end by the addition of side tanks. The remainder, with slight 

modifications, were built between 1907 and 1913, No.75 (now2075) being put into service in January, 1910. Most of the class 

mere built as super-heater engines, and the rest were so converted in recent years. When newly built the engines were used on 

local, as well as the principle express, trains, including through trains between Rugby on the former L. & N.W.R. and Brighton.

Engine No. 2075 wrrs last under general repair in March, 1934, mileage since then being 44,908; bet.ween this general repair 

and the previous one mileage was 61,316 and the total mileage to the data of the accident was 810,399.

Report and Evidence.

7. This train is booked to leave Brighton at 5.18 pm., East Grinstead at 7.5 p-m. and East Croydon at 7.59 p.m. running thence 

non-stop to Victoria in 16 minutes, representing an average speed of 39.61 miles per hour for the 10 miles 45 chains; the 

working book passing times allow 7 minutes for the 5 miles 14 chains from Windmill Bridge Junction to Balham Junction, or 

44-38 miles per hour. This non-stop timing from East Croydon to Victoria has been in force since January, 1933, prior to which 

a stop was included at Clapham Junction, but the 7 minute timing, pass to pass, from Windmill Bridge Junction to Balham 

Junction has stood for over six years.

For the whole of this time the train has been worked from East Grinstead, where engines are changed, to Victoria by a tank 

engine, and regularly for the last three or four years by an engine of the I3 class, this being the return engine working on the 

5.10 pm.from Victoria which arrives at East Grinstead at 6.23 p.m.; 42 minutes are thus available at East Grinstead for 

locomotive purposes which, I was informed, is sufficient for the necessary routine attention between trips but hardly allows a 

margin for turning, which can only be done by means of a triangle formed by St. Margaret's Junction at East Grinstead and a 

connecting goods line, the use of which is restricted to engines of moderate weight (e.g, the I.3 class); there is no turntable.

Driver J. Rugman, who had 36 years' service with the Company and 23 as a driver, worked the 5.10 .m.train from Victoria to 

East Grinstead, with engine No. '2075, running cl!imney first. The engine was generally in very good order and his examination 

at East Grinstead disclased nothing amiss before he started on the up journey, bunker first, at 7.5 p.m.

The run was perfectly normal as far as Mitcham lane Bridge. Leaving East Croydon one minute late, he had the regulator 

barely open, about half the first valve, and the screw reversing gear about 2 1/2 in. out of mid-gear, continuing at this setting 

until the derailment. Just after passing Mitclmm Lane Bridge at the normal speed of about 55 miles per hour, there were four or 

five oscillations of a rolling nature followed at once by a grating noise; he thought the first roll was to the left, but was not sure. 

Severe oscillation being unusual at this point, he immediately made a moderate application of the brake, not thinking it 

advisable to brake hard. As sped was reduced the grating sound changed to bumping and he made a full brake application 

about 100 yards before the train came to a stand.

He described the oscillation as violent but not enough to throw him off his feet; it was soft in character and there was no severe 

jolt such as might be caused by an axle box striking the horns. He had frequently driven engines of the I.3 class and this was the 

first time he had felt any serious movement on one of them; they had a reputation for occasional rolling, though they did not ( 

box or  nose). He was emphatic that here was no unusual oscillstion before passing under the bridge and, when the rolling 

started, he was not alarmed, but took action to steady the speed of the train as he always did when experiencing a roll with a 

tank engine at speed. He had worked the same train on the previous days of the week with a similar class of engine and with 

engine No. 2076 on. the Wednesday; in each case the engine was '' chimney first down the line and bunker first up the line ", and 

bad not experienced any oscillation at this pion t during the week.

At the time of derailment the tanks were approximately half full, and there was about 30 cwt. of coal in the bunker. After  re-

railment ‘he worked the empty stock with the same engine as far as Clapham Junction and noticed nothing wrong with the 

engine during this trip.

Fireman W. Ayres. with 18 years' service with the Company and 17 as a fireman, was certain that the oscillation began earlier, 

between the trailing points of Streatham North Junction and Mitcham Lane Bridge. There was no oscillation through the 

trailing junction, which he referred to it's a " good junction ". The oscillation was a side to side roll, not particularly severe, and 

no worse than the normal oscillation experienced at times with this class of engine when running fast, and be did not think there 

was "anything unusual happening ". The oscillation did not increase, and there were three or four rolls and then bumping as if 

the wheels were riding on the chairs; the rolling was soft, without jolt, and he contrasted the motion with that of the 4-4-0 

tender engines (B.4class) which " came down with a bang at the end of the roll '. He knew the I3 class of engine well, and had 

not noticed any difference in the motion whether running chimney or bunker first. 

Speed was about 55 miles per hour, it being at this point that the highest speed was attained by non-stopping trains between 

East Croydon and Victoria; but he had travelled faster here on other trains. 


At the time of derailment the tanks were approximately half full, and there was about 30 cwt. of coal in the bunker. After  re-

railment ‘he worked the empty stock with the same engine as far as Clapham Junction and noticed nothing wrong with the 

engine during this trip.

Fireman W. Ayres. with 18 years' service with the Company and 17 as a fireman, was certain that the oscillation began earlier, 

between the trailing points of Streatham North Junction and Mitcham Lane Bridge. There was no oscillation through the 

trailing junction, which he referred to it's a " good junction ". The oscillation was a side to side roll, not particularly severe, and 

no worse than the normal oscillation experienced at times with this class of engine when running fast, and be did not think there 

was "anything unusual happening ". The oscillation did not increase, and there were three or four rolls and then bumping as if 

the wheels were riding on the chairs; the rolling was soft, without jolt, and he contrasted the motion with that of the 4-4-0 

tender engines (B.4class) which " came down with a bang at the end of the roll '. He knew the I3 class of engine well, and had 

not noticed any difference in the motion whether running chimney or bunker first. 

Speed was about 55 miles per hour, it being at this point that the highest speed was attained by non-stopping trains between 

East Croydon and Victoria; but he had travelled faster here on other trains. 

8. Driver A. E. Mills and Driver A. Hoper, both experienced drivers, gave evidence as to the steady riding qualities of the I3 

class of engine at speeds of 50 m.p.h. and over. On the day in question Driver Mills drove engine No. 2090 (I.3 class) on the 

9.30 a.m. train from Tunbridge Wells West to Victoria, the timing of this train between East Croydon and Balham Junction being 

the same as that of the train concerned in the accident. He noticed no peculiar oscillation at any point in the journey and 

estimated his speed passing Streatham North Junction as 45 to 50

Driver Hoper on the same day worked the 4.51 pm. from Uckfield toVictoria with engine No. 2004 of the I1 class, a somewhat 

similar tank engine to those of the I3 class, of the 4-4-2 type, but with 5 ft. 6 in, coupled wheels; he passed the point of the 

derailment at the usual speed of 55 to 60 m.p.h. and noticed nothing unusual. He remarked that it was unusual to get a roll at 

that point, although there was generally a slight roll approaching Balham, “ though nothing much there”. There was no 

difference in motion whether running chimney or bunker first.

Motorman W. J. Packham, with 16 years experience as a driver, and motorman J. Broadbridge with 24 years, both drove 

electric trains over this section of line less than half-an-hour before the accident. Neither man experienced any unusual 

movement and the former said that although he always reported a rough piece of the road, this particular section bad no special 

reputation for bad riding. 

9. Guard S. Emery, with 27 years' service with the Company and 25 as guard, said that he left East Croydon at 8 p.m., one 

minute late; he was looking through the side look-out of his van, the last vehicle of the train, and estimated that be speed 

Streatham North Junction at 45 m.p.h., the usual speed. Until his van valve was operated by the driver’s emergency brake 

application passing through Tooting Bec Road bridge, nothing abnormal had occurred on the journey; he did not notice he the 

first partial brake application. Although he realised from the emergency braking that something was wrong, he was unaware of 

any derailment until he met the fireman; after that he took steps to protect the train. He observed no flashes or short circuiting 

from the conductor rail, and I was informed that the circuit breakers were not affected.

Sigualman W . Nunn, who bad been a signalman for 28 years and for 20 years in Streatham North Junction box, said the train 

passed his box at the usual speed or 45 m.p.h. and remarked that the Brighton electric trains usually passed the box at about 50 

to 60 m.p.h. For a fast train he normally got the " Out of Section " signal from Balham Intermediate signal box in one minute 

and from 3 Balham Junction box in two minutes when Balham Intermediate was switched out. 

He noticed nothing peculiar about the train as it passed him. His evidence was confirmed as to times and usual train speeds by 

signalmam A. E. English of Balham Intermediate box, who said the train was going quite slowly when it first came into his view. 

He noticed the time was 8.09 p.m.

Analysis of the signal box timings for this train on the seven weekdays up to and including the day of the accident indicated an 

average speed of the order of 57 m.p.h. between Windmill Bridge Junction and Streatham North Junction, and rather higher 

between Selhurst. and Streatham North Junction. 

10. Sub-ganger J. Terrell, who had 8 years' service with the Company and 6 years as sub-ganger of the length in question, had 

been acting as ganger since the ganger’s retirement a week before. He examined the up main line at about 3.30 p.m. on the day 

of the accident nod found it in condition. At the last general fettling at this point two months ago he had beater packed a few 

joints, a lift, of perhaps 1/4in. to 1/2in. No joints were attended to on the day of the accident., but there was a joint left unfilled 

four rail lengths in rear of the point of derailment: this and a few other joints on the length had been shovel packed a month or 

six weeks previously, and, being “ on the full side “. had been left unfilled to encourage them to settle down. He had 

experienced little difficulty in keeping the up main in line since the curves were adjusted about five years ago and no more than 

the usual trouble on a line carrying heavy traffic in keeping the joints and the line generally to a good level. He had not himself 

gauged the line before the accident, but his predecessor used to do this regularly every six weeks or two months. 

Permanent-Way Inspector H.A. Gabriel, who had 33 years' service with the Company and over five years as Inspector in charge 

of this district, confirmed that since the cutting was drained there had been no particular trouble with maintenance on this 

section; no general lift had been carried out since he had been in charge.

There were instructions that Permanent-Way Inspectors should ride over the whole of the lines in their district on the footplate 

or in the motorman's cab once in every month noting this in their weekly return to the Divisional Engineer’s office, and there 

was not much difficulty in complying with these instructions. On the 1st July he had ridden over the up main line in the cab of a 

fast electric train and again on the 23rd July, although it was probably about six months ago that he was last over the line on 

the footplate of a steam train, the latter being now comparatively few in number. He had ridden on tank engines of the I.3class, 

and on tender engines of the U class over the up main line and had never noticed any undue movement at this place. He also 

made a habit of asking drivers if they had any complaints about the road, and he had had none with regard to this section of be.

Assistant Chief Inspector P. King had only had general charge of this section for the last six months; during that time, however 

he had had no complaints from gangers. He personally gauged the line in rear of the point of derailment about two hours after 

the accident and found nothing amiss. He gave assurance that no fettling or lifting of the line had been carried out between the 

time of the accident and my examination of the site other than the necessary repairs to the track in advance of the point of 


Chief Inspector W. Sears, who had been Permanent.-Way Inspector for 20 years and Chief Inspector for six months, had for the 

last seven years acted as Assistant to the Permanent Way Superintendent of the London (East) Division. He was unable to 

advance any theory as to the cause of the derailment. He referred to the improvement in stability of the track at this point since 

the draining operations six or seven years ago, at which time the old “pebbly” ballast ws replace by Meldon granite above 

sleeper bed level. On the 6th June he made an inspection with a view to arranging and additional ballast; this was in fact a 

continuation of the lift and additional ballast; this was in fact a continuation of the lift already carried out to Selhurst from the 

north and to Balham Intermediate signal box from the South. There had been a slight increase in the work required to keep the 

road in order since the electric services to Brighton started in January, 1933, but be had bad no complaints from the gangers or 

the men on this section with regard to under staffing, the strength of this gang (seven men) complying with the man-power 

formula for the highest class of line. Neither he nor Inspector King made a regular practice of riding on the footplate. which 

was left ho the Permanent-Way Inspectors, but he did so when he could. A week before the accident he rode over the up main 

line on the footplate of an engine of the I3 class, running chimney first; he passed the point of derailment about- 43 to 50 m.p.h. 

but felt no undue oscillation.

He remarked that the side wear of the rails had become worse since the introduction of the electric services. I noted that 

whereas the side rear of the high (cess) rail was slight but constant up to a point 50 yards north of Mitcham Lane Bridge, 

thereafter round the short 60 chains right-handed curve it, varied in waves from negligible to considerable; the waves, however. 

were not regular, points of maximum wear varying from 17 ft. to 70 ft. apart and of minimum wear 31 ft. to 70ft. 6 ins. In several 

cases maxima and minima corresponded with the centre and joints respectively of the 45ft. rails. This sudden change from 

constant (and slight,) to irregular wear in places serious. is noteworthy. I was informed that this type of wear had been noticed 

since the introduction of the Brighton multiple-unit services and was attributed to the hunting action of the motor-driven bogies. 

Wear was not great at the initial point of derailment, and the heaviest side-cutting noted occurred at the middle of a rail 54 

yards in rear. 

11. Engine No. 2075, less than three months before the accident, under went light repairs, including the following work:-bogie 

tyres returned, bogie axle-boxes refitted, bogie swing-link bushes renewed, right driving spring renewed washers fitted at.the 

bottom of the pony springs. The periodical examination of the pony truck was made on 17th December, 1934. and of the tyres 

and wheels on 20th June, 1935.

The engine was examined at Stewart’s Lane depot on the morning after. the accident. by leading titter F. W. R. Curry, who found 

no mechanical defect and no parts missing He had the engine weighed on the 23rd July,  and the

greatest discrepancy was found at the right-hand pony wheel (left leading as running bunker first) namely 7 tons 18 cwt. actual. 

compared with the designed weight-of 8 tons 7 cwt. 2 qrs. With long experience of this class of engine he had noted no particular trouble with their “ running gear .. 

Assisted by the Company’s officers, I made a detailed examination of engine No. 2075 at Brighton Works on the 30th July. The 

flanges of the bogie, and pony wheels were turned to the standard “A'' or thick profile, those of the coupled wheels having the 

thinner “ G" profile; all were of the standard depth of 1 1/8in. The bogie tyres and flanges were practically unworn having been 

recently re-turned. Wear of he coupled tyres varied from 1/16 in to 3/32 in, hollow on the tread and, 3/64in. to 1/16 in. at the 

root of the flange; wear of the pony tyres was similar in amount at the tread. that at the root of the flange being 1/16 in. and 3/32 

in. for right, and left-hand wheels respectively.

There was considerable scoring and bruising of the treads and flanges of the coupled wheels consistent with the striking of 

chairs and fish-bolts by the wheels as they ran derailed. but it was not possible to detect with certainty a bruise at the tip of the 

flange of the right driving wheel to correspond with the bruise on the rail-end referred to earlier in this Report. 

The increases from standard will be noted, mileage since the last genera1 repair being 44,908, particularly the 13/32 in. 

(5/16in. .+ 1/32 in.), increase in respect of the pony axle, allowing a total free movement side to side (including journal 

clearance) of 27/32in. before the spring begins to exert its controlling force.

After the accident all bearing springs and the pony side control spring were tested for deflection, which in the case of the 8 coil 

springs of the bogie and of the pony control coil spring did not vary materially from design. The camber of the four springs of 

the coupled wheels under a test load of 7 tons 10 cwt. varied from 1 3/16in. to 1 5/16 in. as a against 1 in. designed, the sixth 

late of the left trailing spring being found broken 5 in. from one end. The designed camber of the pony bearing springs under a 

test load of 6 tons is also 1 in. ; as tested with this load after the accident the camber of the right-hand spring (left, leading, as 

running bunker first) was 1 3/16in. and of the left-hand spring practically correct at l in. bare, the top plate of this spring being 

found broken in the buckle. Except for the two fractures mentioned, the springs were in good condition.

There was no evidence that the axle boxes had been binding in the guides; examination of the axle boxes of the coupled wheels 

showed in each case that the hexagon-headed set screw, fitted at the underside of the keep to secure the keep pin, had been 

crushed, corresponding marks being found on the hornstays. Similar damage to these set screws had also been noticed 

occasionally by Leading Fitter Curry when examining engines of this class; this was not frequent and in his opinion it had 

invariably resulted from a derailment.

Inspector E. G. Read, attached to the Locomotive Running Department, confirmed this opinion, there being 1 1/2in. normal 

clearance between the hornstays and the keeps. He knew these engines well both from examining them and from riding on the 

footplate; they were “ nice engines for riding " and rolled little at high Speed; this would only occur at a soft place in the road 

and under ordinary conditions he did not think they would ever roll to an alarming extent.

12. On the 2nd August, accompanied by Mr. Sheppey, Eastern Divisional Locomotive Running Superintendent, I travelled on the 

footplate of an engine of this class, No. 2023, running bunker first when working an up semi-fast passenger train from Oxted to 

Victoria, a distance of 2o 1/2 miles; Rugman was the driver.

This engine hod worked 52,484 miles since the last general repair in July, 1934, rather more than the mileage of engine No. 

2075. The train comprised six bogie coaches and one horse box, weighing approximately 190 tons, and was booked to leave 

Oxted at 10.09 a.m.,running the eight miles non-stop to Sanderstead in 13 minutes, an average speed of 36.9 m.p.h.; from 

Windmill Bridge Junction to Balham Junction, pass to pass, the booking is seven minutes, or 44.36 m.p.h., the same timing ,as 

that of the train concerned in the accident.

For the first 2 1/2 miles from Oxted speed up the rising gradient did not exceed 35 m.p.h., but on the following falling gradients 

and reverse curvature to Sanderstead a speed of slightly over 60 m.p.h. was attained; this track is not electrified, and I 

understand that the up line here has been recently relaid.

Leaving East Croydon 1 noted that the regulator was not opened beyond the first valve. From Windmill Bridge Junction, which 

was passed at 30 to 35 m.p.h., speed gradually rose down the falling gradients to over 60 m.p.h. at Streatham Common Station. 

It was still increasing when the train was steadied by a slight brake application, passing the site of the accident at about 60 

m.p.h., after which speed was reduced, Balham Junction (50 m.p.h. speed restriction) being passed at about45 m.p.h.

On the two stretches where a sped of the order of 60 m.p.h. was attained, riding was quite steady, with no appreciable rolling or 

nosing movement. Rounding the curve of 34 to 53 chains radius at about 50 m.p.h approaching Balham Junction opinion, 


My short experience on the footplate leads me to concur in the evidence given as to the good riding qualities of this class of 




13 The derailment of a well-balanced engine on track which is intact ( there was no evidence of absence of keys due to high 

temperature) and  maintained to a high standard is difficult to ascribe to any one cause, although the actual sequence of 

derailment in this case is open to little doubt. To account for this accident, therefore, a combination of factors must be sought, 

such as speed of the train, the characteristics of the road at the site, and the design and condition of the engine.

The initial derailment to the left of the trailing coupled wheels must have been brought about by heavy side pressure, aided in 

all probability by temporary relief of weight. on the left-hand wheel. Starting from this premise, the causes which map have led 

to this state of affairs must be considered.

14. Speed was undoubtedly high at the time of derailment, which occurred at the end of some three miles of falling gradients. 

According to driver Rugmam, the engine had been steaming, though lightly, since leaving East Croydon; the load consisted of 

three bogie coaches only, and this class of engine with 6 ft. 7 1/2 in. wheels and piston valves can freely attain high speed, as I 

myself observed from the footplate with more than double the load. Furthermore, signal-box timings of the train concerned 

indicated an average speed of nearly 60 m.p.h. from Windmill Bridge Junction to Streatham North Junction; although such 

timings should be accepted with reserve as sole evidence of speed over a short distance, they afford confirmation of an estimate 

arrived at by other means. Allowing for observance of the 40 m.p.h. restriction at Windmill Bridge Junction, this average would 

involve the attainment of well over 60 m.p.h. at the foot of the gradient. In spite of the estimate of 45 m.p.h. given by guard 

Emery and signalman Nunn, whose evidence in this respect I discount, I am therefore of the opinion that the speed of the train 

when the derailment took place cannot have been less than 65 m.p.h. and may well have been higher. Both enginemen thought 

the speed to be 55 m.p.h., but the existence ot the 60 m.p.h. restriction through Streatham North Junction, of which driver 

Rugman was aware, should be borne in mind. I do not however, regard the distance run by the train after the derailment, 

namely, 540yards. as evidence of speed, since driver Rugman wisely made only a light application of the brake on first feeling 

the unusual movement..

15. With regard to the characteristics of the road, the junction and the succession of short curves of varying radius demand 

compromise in respect of superelevation. There is a length of tangent of 50 yards under Mitcham Lane Bridge on which 

superelevation varies from 1 1/2 in. to 2 1/8in., though the highest rate of variation in this length is 1/4in. in half a length of 45 

ft. rail. Although this class of engine is not markedly sensitive to tract variations in line or level, I think it is possible that the 

existence of appreciable superelevation on tangent track, unavoidable at this point, combined with a speed that was certainly 

high having regard to the varying (though moderate) curvature, initiated rolling of the engine. Although evidence was 

forthcoming that rolling was unusual ere in spite of moderately high normal speeds. I do not regard this as precluding the 

possibility of rolling being initiated from this cause on a specific occasion. The reaction of a locomotive to the track at speed 

cannot obey rigid laws: without the damping effect of a separate tender, a tank engine is inherently more sensitive to track 

variations and momentary conditions may arise, although perhaps rarely, when contributory factors, such as weight distribution 

according to the load of water and fuel, surging of water in the tanks (which were about half empty at the time of derailment), 

spring periodicity, and possibly the phase of them hammer blow, may all be favourable to the building up rather than to the 

damping out of on incipient roll.

Nevertheless, I do not think that the rolling can have over become really severe; Driver Rugman was not alarmed. and Fireman 

Ayres, who was a particularly good witness, referred to it as nothing out of the ordinary. The evidence of these two men is 

conflicting which is understandable, as to the exact point at which the rolling started; although Driver Rugman thought this to 

be after Mitcham Lane Bridge when it started. Fireman Ayres was emphatic that it began between the trailing junction and the 

bridge; on the other hand it is significant that the commencement of the rolling was approximately coincident with passage over 

the length of tangent immediately following which, it should be noted, the waves of side wear on the high rail were first 

observed. Although I do not think that the side wear directly contributed to derailment, its presence in this form suggests that a 

certain unsteadiness in running may have been prevalent at this point, possibly due to the presence of superelevation on tangent 


16. Although the increase from standard of axle box side play of engine No. 2075 was not abnormal in view of the mileage run, 

it cannot be overlooked that,9/16 in. wear had taken place between the pony casting and the main frame allowing a total 

uncontrolled side play to the pony axle, including axle box clearance, of  27/32 in.

Initial derailment occurred on a leaving transition from a 60 chain curve; regular displacement of the pony on this curvature 

would be slight and probably insufficient, with this amount of free play to bring the pony control spring into action. Guiding of 

the engine would thus devolve on the right trailing coupled wheel of large diameter and less favourably situated in respect of 

leverage. High flange pressure would result: accentuated by the usual nosing action round the curve although this is not unduly 

pronounced in engines of the I3class. Once the rolling started, temporary relief of weight would occur on alternate sides of the 

engine; should a roll to the right have coincided with the upward or negative phase of the hammer blow (2.68 tons at 45 r.p.s. or 

64 m.p.h.) of the right-hand trailing anp pled wheel, the combination of heavy flange pressure and relief of load would have set. 

up conditions favourable to climbing and subsequent derailment. In this connection it, is noteworthy that the spring deflection 

tests showed that the right.-hand pony bearing spring was appreciably less resilient than standard (1 9/16 in. camber under 6 

ton load as against 1 in. designed), which might allow it to assume momentarily more than its share of the load to the further 

relief of weight on the right trailing coupled wheel.

17. Reference was made by sub-ganger Terrell. who was considered to be a reliable man, to a rail joint which had been left 

opened out, or unboxed, four rail lengths in rear of the point of derailment, although on my inspection of t be site on the 31st 

July this joint had been filled in and, with the neighbouring joints. appeared to be of good level. I do not think that this can have 

had any bearing on the derailment. in view of the independent evidence of two steam train drivers and two motormen of electric 

trains. all of whom had passed over the site on the up main at hi$ speed on the day in question (the motormen of the two electric 

trains a few minutes before the accident) and had felt no unusual movement.

Remarks and Recommendations

18. While it is not possible to define with certainty the exact cause of this derailment. I feel that Driver T. Rugman must have 

been travelling faster than he realised and chat the most likely cause was too high a speed (over 65 m.p.h.) having regard to the 

two contributory factors, namely the reduced guiding effect of the pony axle, which was leading. and the varying curvature of 

the track, which necessitated appreciable superelevation on tangent. I do not consider, however, that the maintenance of the 

track was open to material criticism, having regard to its age and the punishing effect of the heavy multiple-unit traffic.

19. Although the 60 m.p.h. restrict ion through Streatham North Junction, if observed, should preclude the speed at any rate of 

steam trains, rising appreciably higher before speed is reduced for the 50 m.p.h. restriction at Balham Junction less than 1 1/2 

miles further on, I think it is questionable whether speeds of this order through the varying curvature at the site of the accident 

are not sufficiently high to permit of dangerous oscillation, particularly of a tank engine, when all conditions are favourable to 

its development.

Furthermore, I doubt whether a speed restriction of 60 m.p.h. through Streatham North Junction is sufficiently below the 

general level of speed at this point both of steam and electric trains to make much impression on a driver’s mind. The restriction 

therefore, is probably disregarded in practice, and under favourable conditions, as were present in this case, such as s free 

running engine, a light train running a little late, and good weather, speed may well rise to an undesirable limit. The Company 

is carrying out s regular programme of curve realignment some 234 miles of single track having been dealt with since January 

1933. The up main line between Streatham North Junction and Balham Junction has not yet been realigned, but I understand 

this is in hand although a preliminary chord survey does not appear to have disclosed any marks irregularity. I think the 

Company should consider, in view of all the possible traffic conditions, the desirability of imposing a speed restriction lower 

than 60 m.p.h. at this place, pending further consideration when this realignment is competed.

Generally, with regard to speed restrictions in the congested suburban area, I consider that the question o€ definition by visual 

means merits serious consideration. There are six permanent restrictions varying from 30 to 80 m.p.h. in the 10 1/2 miles on the 

up main line between East Croydon and Victoria; a driver on a routes such as this, where the block sections are short, is fully 

occupied in observing signals, and it appears that there is a risk that he may consequently overlook speed restrictions 

committed to his memory, if a visual reminder is not provided.

20. With regard to the diminished guiding effect of the pony truck, this was brought about by wear between the lugs of the 

engine frame and the retaining washers of the pony control spring; this must have increased the liability to derail of the 

following coupled wheels, and it important, therefore. that the designed effect of the pony should be maintained in service, and 

not allowed to diminish through wear. I was informed that it was the practice at running sheds to take up play in the pony 

casting of engines of this class by the insertion of horse-shoe shaped washers between the lugs of the frame and the retaining 

washers of the control springs. Lifting is not entailed, but 1 understand that this work is only done when an adverse report is 

made as to the riding of the engine. This wear had been permitted to develop in engine No. 2075 to the extent of allowing 9/16 

in. uncontrolled side lay m the pony casting; in view of the simplicity of method, it appears desirable that attention in this 

respect should be regular and periodical, rather than occasional as the result of an adverse report from enginemen.

Apart from the development of uncontrolled side play due to wear it is questionable whether an increase in the strength of the 

pony control spring is not desirable in engines of this class. The initial controlling force is 1.05 tons; increase in this initial 

force would undoubtedly throw more guiding effect on to the pony to the relief of the coupled wheels, and the practicability of 

this appears to be for consideration..

21. This is a case where the use of deeper flanges on the engine, as is standard practice of one Company, might possibly have 

had preventive effect. The better angle of contact with the rail of the deeper flange reduces the tendency to begin climbing, or, 

once climbing has started, the greater depth may delay complete mounting of the rail sufficiently long for more favourable 

conditions to be established, and so avoid derailment.

22. It is significant that an engine of this class, running bunker first, became derailed in December, 1932, under circumstances 

which bear a striking resemblance to those of the accident under review. The train was reported to have been approaching 

Balham Junction on the up main line at a speed of 40 to 45 m.p.h . round the left-handed curve of 34 to 28 chains radius, when 

the trailing coupled wheels (leading coupled as running) left the rails to the outside of the curve, the pony and the remaining 

wheels of the engine and train not becoming derailed. No defects in the permanent way or in the running gear of the engine 

were found that could readily have accounted for the accident, which was attributed at the time to a 5/8 in. stud and nut 

becoming detached from the rear sand box and falling on to the rail between the left- and pony and trailing coupled wheels, 

lifting the latter sufficiently to cause derailment; it is understood that this stud and nut, though missing from the engine, were 

not found on the permanent way, although search was exhaustive. I have discussed this derailment with the Company’s officers, 

who now think it possible, on account of the similarity of the two cases, that obstruction by the missing stud may not have been 

the true cause. On account of the remarkably similar circumstances, I cannot avoid the conclusion that these two derailments 

were most likely due to a similar rare combination. of unfavourable conditions.

It appears that under certain conditions the I3 class of engine has a lessened margin of safety o against derailment at speed 

when running with the pony truck leading, particularly when appreciable sloppiness has been allowed to develop; I therefore 

recommend that the engine workings should be re-arranged so that engines of this class may run chimney first when hauling 

trains whose booked timings demand maximum speeds of, say, 40-45 m.p.h. and over. 


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