Safety of EPB and SUB southern EMUs

[contrex]

I grew up with EPBs and SUBs. The first EPB ran the year before I was born; they were withdrawn when I was 43. I was very fond of them, but some of the shine got knocked off in 1991 when I saw what happened at Cannon Street. The old Fotopic "Control we have a problem" collection of accident photos, now at https://andygibbs.zenfolio.com/f1061579691 has some photos of EPBs and SUBS that opened up like cardboard boxes.

 

[Journeyman]

I grew up with EPBs and SUBs. The first EPB ran the year before I was born; they were withdrawn when I was 43. I was very fond of them, but some of the shine got knocked off in 1991 when I saw what happened at Cannon Street. The old Fotopic "Control we have a problem" collection of accident photos, now at https://andygibbs.zenfolio.com/f1061579691 has some photos of EPBs and SUBS that opened up like cardboard boxes.

Absolutely, the things were flimsy as hell, and that's a problem with everything as it gets older - and parts of the EPBs and SUBs, namely underframes and bogies, dated back to the 20s and 30s. Although nothing structural on the 455s is that old, and the Mark 3 bodyshell has good crashworthiness - or at least did for its time - it's clear that as these units age, they will become less safe.

 

[DustyBin]

I grew up with EPBs and SUBs. The first EPB ran the year before I was born; they were withdrawn when I was 43. I was very fond of them, but some of the shine got knocked off in 1991 when I saw what happened at Cannon Street. The old Fotopic "Control we have a problem" collection of accident photos, now at https://andygibbs.zenfolio.com/f1061579691 has some photos of EPBs and SUBS that opened up like cardboard boxes.

I didn’t know about that site, extremely interesting, thanks!

Absolutely, the things were flimsy as hell, and that's a problem with everything as it gets older - and parts of the EPBs and SUBs, namely underframes and bogies, dated back to the 20s and 30s. Although nothing structural on the 455s is that old, and the Mark 3 bodyshell has good crashworthiness - or at least did for its time - it's clear that as these units age, they will become less safe.

It’s not that they get less safe as they age, they simply weren’t safe to start with. Well they were, so long as they didn’t end up in an accident.... The underframes were fine, it’s the combination of heavy underframes and non-structural bodies that was the inherent problem.

 

[Journeyman]

It’s not that they get less safe as they age, they simply weren’t safe to start with. Well they were, so long as they didn’t end up in an accident.... The underframes were fine, it’s the combination of heavy underframes and non-structural bodies that was the inherent problem.

Well, they weren't safe to start with, AND they got less safe with age. A lot of things do, if they're made of steel and begin to corrode. But yeah, the bodywork of EPBs, in particular the SR designed ones, felt like it was made of matchsticks. It was designed for maximum internal width to allow 5/6 a side seating, and as a result was extremely thin with only small reinforcing beams.

 

[DustyBin]

Well, they weren't safe to start with, AND they got less safe with age. A lot of things do, if they're made of steel and begin to corrode. But yeah, the bodywork of EPBs, in particular the SR designed ones, felt like it was made of matchsticks. It was designed for maximum internal width to allow 5/6 a side seating, and as a result was extremely thin with only small reinforcing beams.

The SR design units were obviously pre MK1 and even less crash resistant. To be fair to them they were fairly typical of their generation. Also, they weren’t meant to collide with each other and many of the accidents they were involved in simply wouldn’t happen today. Preventing accidents from happening in the first place is key to safety. An A350 is extremely strong and is constructed from all kinds of high tech materials, but if it decides to fall from the sky at 35,000ft you may as well be aboard a 727.

 

[Journeyman]

The SR design units were obviously pre MK1 and even less crash resistant. To be fair to them they were fairly typical of their generation. Also, they weren’t meant to collide with each other and many of the accidents they were involved in simply wouldn’t happen today. Preventing accidents from happening in the first place is key to safety. An A350 is extremely strong and is constructed from all kinds of high tech materials, but if it decides to fall from the sky at 35,000ft you may as well be aboard a 727.

Oh, I agree, and one of the biggest factors in the reduction of casualties on the railway is TPWS, which has prevented vast numbers of the sorts of collisions that used to be routine.

 

[43096]

Oh, I agree, and one of the biggest factors in the reduction of casualties on the railway is TPWS, which has prevented vast numbers of the sorts of collisions that used to be routine.

You only have to look back at old magazines and the works reports in them to see just how many collision damage repairs were ongoing at any one time.

 

[contrex]

The idea used to be that you protected passengers and crews by keeping the trains apart with signals. often semaphores, and it could get foggy, and drivers could get tired. Once in a while a whole load of people got mangled when the (big) holes in the (not very many) slices of cheese lined up (Harrow, Lewisham). Last resort, prosecute the driver for manslaughter.

 

[yorksrob]

EPB's, SUB's etc represented a an increase in safety over their wooden bodied predecessors.

Fortunately someone has already mentioned that the Mk1 EPB's themselves represented an improvement in crashworthiness over their Bullied designed brethren.

In spite of them being patently less crashworthy than modern rolling stock, I would still feel (and be) a lot safer in an EPB of any age, than in many everyday settings, for example travelling along a motorway at speed, or walking along a busy main road.

 

[30907]

Absolutely, the things were flimsy as hell, and that's a problem with everything as it gets older - and parts of the EPBs and SUBs, namely underframes and bogies, dated back to the 20s and 30s.

The re-used bits of SR stock weren't the problem, though, surely? Apart from the bodywork (which was basically not loadbearing longitudinally) the only other feature which is mentioned in the Cannon Street report summary is the centre buffer/coupler fitted to SUBs and all EPBs.

Sorry, I see DustyBin has made a similar point.

 

[big all]

Whilst the practice of reusing old chassis was common you will find all the damage tends to be on internal couplings as it's no more than a 3 link under a single buffer on one vehicle with a wooden block on the other making a perfect "ride up and over" situation to absorb the forces involved.

 

[Snow1964]

The re-used bits of SR stock weren't the problem, though, surely? Apart from the bodywork (which was basically not loadbearing longitudinally) the only other feature which is mentioned in the Cannon Street report summary is the centre buffer/coupler fitted to SUBs and all EPBs.

Sorry, I see DustyBin has made a similar point.

The main problem was not the underframes (which were strong), but the height of the underframes, and lack of anti-climb (the serrated panels).

Everything above the underframe was relatively light construction so in a big collision one frame could be higher and slice through the bodywork of next vehicle. Within the units many simply had a central buffer with chain coupler below, nothing that would keep frames in line if weren’t both on the track

 

[physics34]

The 'cup and cone' modification which was talked about with regards to a possible CIG/VEP rebuild in the 90s wouldve been a relatively cheap way to solve the issues with longitudinal crash worthiness, but sadly nothing was done before the cannon street or clapham crashes. The damage to the SR EPB a cannon street was indeed an eye-opener and although i liked them as trains it was shocking really that they stayed in service for another 7 or so years! Indeed nowadays, tpws wouldve prevented the crash anyway.

 

[Taunton]

Notably, when all-steel vehicles of exactly this design were involved in collisions back in the 1950s, the all-steel design gets praised in the accident report. Of course, they were comparing it to previous wooden-bodied stock, and noting it was far more robust.

The real issue was telescoping, which UK railways never addressed. In the USA they had long done so, with the "Anticlimber" on the end of passenger vehicles (and locomotives), substantial horizontally ridged structures. They don't have to be very deep to be effective. It's notable that in big US collisions, with energy far more than would ever need to be absorbed in the UK, telescoping is unknown and the vehicles instead tend to concertina zig-zag sideways, retaining their structural integrity. Here are some examples of older US locos with anticlimbers prominent at frame level, just above the coupler.

general motors F7 cab unit - Google Search

 

[Mikey C]

The 'cup and cone' modification which was talked about with regards to a possible CIG/VEP rebuild in the 90s wouldve been a relatively cheap way to solve the issues with longitudinal crash worthiness, but sadly nothing was done before the cannon street or clapham crashes. The damage to the SR EPB a cannon street was indeed an eye-opener and although i liked them as trains it was shocking really that they stayed in service for another 7 or so years! Indeed nowadays, tpws wouldve prevented the crash anyway.

Then there was the additional safety risk from the awful compartment EPB carriages as well, where a woman was murdered in 1988...

 

[pdeaves]

Then there was the additional safety risk from the awful compartment EPB carriages as well, where a woman was murdered in 1988...

Well, in fairness, that wasn't a function of EPBs but of compartments generally. It happens that the remaining compartments were in EPBs.

 

[Mikey C]

Well, in fairness, that wasn't a function of EPBs but of compartments generally. It happens that the remaining compartments were in EPBs.

Years after the other such compartments had gone...

 

[yorksrob]

Years after the other such compartments had gone...

The vast majority of the EPB's didn't have them in the last few years.

Notably, when all-steel vehicles of exactly this design were involved in collisions back in the 1950s, the all-steel design gets praised in the accident report. Of course, they were comparing it to previous wooden-bodied stock, and noting it was far more robust.

The real issue was telescoping, which UK railways never addressed. In the USA they had long done so, with the "Anticlimber" on the end of passenger vehicles (and locomotives), substantial horizontally ridged structures. They don't have to be very deep to be effective. It's notable that in big US collisions, with energy far more than would ever need to be absorbed in the UK, telescoping is unknown and the vehicles instead tend to concertina zig-zag sideways, retaining their structural integrity. Here are some examples of older US locos with anticlimbers prominent at frame level, just above the coupler.

general motors F7 cab unit - Google Search

It does surprise me that such a simple device wasn't incorporated into British rolling stock a lot earlier.

 

[Wolfie]

It does surprise me that such a simple device wasn't incorporated into British rolling stock a lot earlier.

NIH l fear....

 

[yorksrob]

NIH l fear....

Ah yes, see what you mean !

 

[edwin_m]

The 'cup and cone' modification which was talked about with regards to a possible CIG/VEP rebuild in the 90s wouldve been a relatively cheap way to solve the issues with longitudinal crash worthiness, but sadly nothing was done before the cannon street or clapham crashes. The damage to the SR EPB a cannon street was indeed an eye-opener and although i liked them as trains it was shocking really that they stayed in service for another 7 or so years! Indeed nowadays, tpws wouldve prevented the crash anyway.

By the time cup and cone was thought of, the units involved at Cannon Street had gone and the remaining Mk1 units had a very short time in service. From what I remember, intermediate gangways between the cars prevented the cup and cone engaging so would have had to be removed - not sure if that was within a unit too but logic suggests it would have been. It would only have worked at the end of a formation if it had collided with another slammer formation also fitted with C&C.

So all in all, a good idea in theory but once people started thinking about the practicalities it was quite rightly binned.

 

[Bald Rick]

I vividly remember Roger Ford describing how this type of stock had the unfortunate problem that, occasionally in an accident, the underframe of the adjacent carriage would come through your seat back.

 

[Wolfie]

I vividly remember Roger Ford describing how this type of stock had the unfortunate problem that, occasionally in an accident, the underframe of the adjacent carriage would come through your seat back.

Hmmm... Rather puts the alleged lack of comfort of "ironing boards" in perspective....

 

[Ken H]

I suspect TPWS has had a bigger effect on fatalities than the new trains. Has there been a severe end on collision since the Mk1 trains were scrapped?

 

[matchmaker]

Notably, when all-steel vehicles of exactly this design were involved in collisions back in the 1950s, the all-steel design gets praised in the accident report. Of course, they were comparing it to previous wooden-bodied stock, and noting it was far more robust.

The real issue was telescoping, which UK railways never addressed. In the USA they had long done so, with the "Anticlimber" on the end of passenger vehicles (and locomotives), substantial horizontally ridged structures. They don't have to be very deep to be effective. It's notable that in big US collisions, with energy far more than would ever need to be absorbed in the UK, telescoping is unknown and the vehicles instead tend to concertina zig-zag sideways, retaining their structural integrity. Here are some examples of older US locos with anticlimbers prominent at frame level, just above the coupler.

general motors F7 cab unit - Google Search

Very true, but rolling stock with buckeye couplers and Pullman gangways was far less likely to telescope than stock with screw couplings and side buffers - compare the results of crashes involving pre-nationalisation stock of LNER or SR design (buckeyes) and LMS and GWR (screw couplings). See photo of the 1937 Castlecary disaster.

 

[Islineclear3_1]

Of course, many shunting mishaps never got reported. I remember many units were under repair for side scrapes etc...

 

[theageofthetra]

I grew up with EPBs and SUBs. The first EPB ran the year before I was born; they were withdrawn when I was 43. I was very fond of them, but some of the shine got knocked off in 1991 when I saw what happened at Cannon Street. The old Fotopic "Control we have a problem" collection of accident photos, now at https://andygibbs.zenfolio.com/f1061579691 has some photos of EPBs and SUBS that opened up like cardboard boxes.

What a fascinating site. Thanks for sharing.

 

[edwin_m]

Very true, but rolling stock with buckeye couplers and Pullman gangways was far less likely to telescope than stock with screw couplings and side buffers - compare the results of crashes involving pre-nationalisation stock of LNER or SR design (buckeyes) and LMS and GWR (screw couplings). See photo of the 1937 Castlecary disaster.View attachment 89970

There's an argument to say that jack-knifing is safer than stopping in line, because it disspates the energy of the collision relatively harmlessly in scraping the coaches over the ground. However either would be safer than telescoping.

 

[43096]

I suspect TPWS has had a bigger effect on fatalities than the new trains. Has there been a severe end on collision since the Mk1 trains were scrapped?

Wasn't TPWS the mitigation that allowed the barmy cup and cone scheme to be binned? Basically prevent trains hitting each other in the first place, which is a better solution.

 

[Bald Rick]

I suspect TPWS has had a bigger effect on fatalities than the new trains. Has there been a severe end on collision since the Mk1 trains were scrapped?

You didn’t need an end on collission for Mk1 coaches to be destroyed. Colwich showed how much safer integral body shells are.

Wasn't TPWS the mitigation that allowed the barmy cup and cone scheme to be binned? Basically prevent trains hitting each other in the first place, which is a better solution.

IIRC they were planned to be delivered at about the same time. However TPWS got ahead, and then the Mk1s replacements were delivered en masse, and the safety benefit of spending money on cup and cone became silly.