Trains that became detached.

[CR165022]

Moderator note - split from:

“Coach becoming uncoupled on a train” at Welham Green - 10/10/2026

Around 3pm, a Moorgate train at Hatfield was held for over 13 minutes. The reason was due to a train in front of it having a coach uncoupled. This is what was written on the National Rail Enquiries page: A coach becoming uncoupled on a train between Welwyn Garden City and Alexandra Palace means...

www.railforums.co.uk

Has certainly happened before, a 150 splitting apart at Leeds springs to mind. Whatever happened however, seems to have been resolved as something has just shunted back into the yard and 2R43 is on the move. Although services are still being diverted through Hertford North for some reason, 1A23 in particular has only just left Stevenage to head down there.

 

[55018ballymoss]

And if you want to go further back, the class 155s (except the former WYPTE ones) were disbanded and made into single car 153s as they had a nasty habit of becoming uncoupled in passenger service...

 

[norbitonflyer]

A work colleage of mine was tarvelling out of paddington on a 6-car class 117 train once when the two units came apart near Westbourne Park. The control and brake hoses had been connected properly, but not the coupling. Train worked fine under acceleration (presumably the rear unit was more powerful) but came apart, and severed the brake pipes, under braking (so presumably the rear unit also had better brakes)

 

[SuspectUsual]

Has certainly happened before, a 150 splitting apart at Leeds springs to mind.

I remember that, I got to Leeds about half an hour afterwards and it was carnage.

Was there ever an official report on what actually happened?

 

[AndrewE]

There was a HST which came apart in service on the ECML, I think the one fatality was a railway employee who was commuting and somehow fell between the 2 separated halves.

 

[Failed Unit]

There was a HST which came apart in service on the ECML, I think the one fatality was a railway employee who was commuting and somehow fell between the 2 separated halves.

We have had a few. I remember the Aberdeen - Kings Cross service splitting at Grantham in recent history

 

[Harpo]

Train division is unusual but rarer on passenger stock.

The oddest one I came across was a detached Turbo left across the down main outside Reading depot by an ECS to the station. It was discovered by a passenger train examining what was believed to be a failed track circuit.

 

[voyagerdude220]

Wasn't there a similar incident involving a Cross Country HST a few years ago? I seem to recall it being at Bristol Temple Meads, the front power car becoming divided from the rest of it's train as it tried to leave the Station northbound.

 

[Acathater]

And if you want to go further back, the class 155s (except the former WYPTE ones) were disbanded and made into single car 153s as they had a nasty habit of becoming uncoupled in passenger service...

I've never heard that tale before. It certainly doesn't fit the usual story of why the 155s were selected for conversion: that their modular design made it easier than the 156s

 

[ChiefPlanner]

A pair of Bletchley's finest 117's came apart one dark morning , running ECS , around Tring. Not bad as it had come off the depot !

 

[Efini92]

I remember that, I got to Leeds about half an hour afterwards and it was carnage.

Was there ever an official report on what actually happened?

IIRC it had just had a refurb. When it was put back together someone had forgotten to put a strap around the coupler arms.

 

[Supercoss]

This brings up the age old debate of HST ‘Alliance ‘ couplers ( a fixed buckeye) versus drop head Buckeye on Mark 1,2 & 3 buffer fitted stock
great care must be taken to perform a pull away test as although “ knuckles’ may be together they may not be locked.
The photos show inner end of power car and Mark 3 Trailer separated detail in a depot, NOT related to this reported separation .

 

[westcoaster]

When we used to couple 319's, you always had to make sure the butterfly clip protruded out the back of the coupling head and you could see daylight between them.

 

[Falcon1200]

I've never heard that tale before.

Me neither! Is it not more that BR identified a need for single-car units and Class 155 was the most suitable provider? And of course, a small number of Class 155 is still in service today.

 

[SuspectUsual]

Me neither! Is it not more that BR identified a need for single-car units and Class 155 was the most suitable provider? And of course, a small number of Class 155 is still in service today.

I don’t believe it can be true.

Seven class 155s remained, from memory these were owned by the then WYPTE and they refused to have theirs converted.

If there was a safety-related reason for the conversions then that would have overridden who the owner was, and in any event 153s have worked in multiple ever since.

 

[Swedenorer]

Didn't a GWR 158 separate at Chichester a few years ago?

 

[Trainman40083]

Me neither! Is it not more that BR identified a need for single-car units and Class 155 was the most suitable provider? And of course, a small number of Class 155 is still in service today.

Maybe more British Rail needed more units and conversion to single cars was the DfT solution.

 

[Whisky Papa]

About 10 years ago, the train I was returning from work at Bradford Interchange on had a separation just west of Sowerby Bridge, although it was rectified in fairly quick time and we continued. It would have been departing Bradford around 1614, and it was still daylight.

The train was usually a 2-car 158 strengthened with a 153, which was at the leading end from Bradford, although occasionally this was not available and even more occasionally a 150 substituted the 158.

I assume it was a normal formation and the separation was between the 158 and 153 rather than within the 158, but my memory is surprisingly vague; other than making myself known to the conductor and standing guard in the vestibule at one end of the 'gap' I am struggling to pin down anything further.

Does anyone have a better memory or access to records?

Maybe more British Rail needed more units and conversion to single cars was the DfT solution.

That fits what I understood at the time, I wasn't aware 155s had any uncoupling issues before conversion.

 

[High Dyke]

We have had a few. I remember the Aberdeen - Kings Cross service splitting at Grantham in recent history

That may be the incident I was called to (Frinkley Lane near Barkston). If it is, the offending vehicles parted because the coupler on one coach wasn't secured properly. It had become unscrewed with the nut from it in the sump and the rest of the coupling attached to the other vehicle.

 

[CW2]

I believe the issue with the 155s was with the doors, not the couplings. They had a nasty habit of blowing open when moving at speed, causing the interlocks to trip, with a full emergency brake application (and associated wheelflats).

They were withdrawn en masse because of this, which resulted in a massive relocation of class 156s from Inverness to Cardiff overnight, so the 156s could take over the Marches etc.

The 155s stayed on the naughty step for some time before refurbishment and reinvention as 153s.

 

[Failed Unit]

That may be the incident I was called to (Frinkley Lane near Barkston). If it is, the offending vehicles parted because the coupler on one coach wasn't secured properly. It had become unscrewed with the nut from it in the sump and the rest of the coupling attached to the other vehicle.

I think it is, I do recall something small was missing (I thought it was a clip) which the the vibration of train on its journey resulted in it parting.

== Doublepost prevention - post automatically merged: Yesterday at 13:40 ==

I believe the issue with the 155s was with the doors, not the couplings. They had a nasty habit of blowing open when moving at speed, causing the interlocks to trip, with a full emergency brake application (and associated wheelflats).

They were withdrawn en masse because of this, which resulted in a massive relocation of class 156s from Inverness to Cardiff overnight, so the 156s could take over the Marches etc.

The 155s stayed on the naughty step for some time before refurbishment and reinvention as 153s.

They did have problems with the doors, blowing open sounds really back for plug doors. When that kicked off they borrowed the unit from Cleethorpes - Barton to cover which have the line no service for a short period of time

 

[edwin_m]

I sort of recall a separation between units (158s at Glasgow Queen Street?) that led to a rule that after coupling Sprinters the driver should attempt to drive one away with the brakes applied on the other. Presumably this can only be done after physical coupling but before the control circuits are connected.

 

[Ashley Hill]

Some years ago a pair of 143s separated between Teignmouth and Newton Abbot. The front set carried on to Newton Abbot. I cannot remember the full details.

 

[Failed Unit]

I sort of recall a separation between units (158s at Glasgow Queen Street?) that led to a rule that after coupling Sprinters the driver should attempt to drive one away with the brakes applied on the other. Presumably this can only be done after physical coupling but before the control circuits are connected.

Where there similar problems with networkers, where a rule was put into place they couldn’t be coupled on curved platforms. I am sure 317s splitting in service was the excuse used for keeping the corridor connections closed towards the end of their life.

 

[Harvester]

In 1958, Britannia 70014 detached from its tender at speed while hauling a passenger train, when the tender drawbar snapped.

The loss of vacuum caused the tender and train brakes to apply and stop that portion, but the solo loco carried on as a runaway with the crew in a desperate situation.

They had no control of the boiler and with the water supply severed, had to manually drop the fire to prevent a possible boiler explosion. Eventually the loco was brought to a stop, by the levelling gradient, and reversing gear.

 

[Kentish RYS]

In 1958 Britannia 70014 detached from its tender at speed while hauling a passenger train, when the tender drawbar snapped. The loss of vacuum caused the tender and train brakes to apply and stop that portion, but the solo loco carried on as a runaway with the crew in a desperate situation. They had no control of the boiler and with the water supply severed, had to manually drop the fire to prevent a possible boiler explosion. Eventually the loco was brought to a stop, using the mechanical handbrake and reversing gear.

That's sounds pretty hairy whatever, but isn't the handbrake on the tender usually on tender locos? I don't know the BR Standard/Britannia loco brake design (steam or vac or combination and on which bits) to know how the loco would stop

 

[Harvester]

That's sounds pretty hairy whatever, but isn't the handbrake on the tender usually on tender locos? I don't know the BR Standard/Britannia loco brake design (steam or vac or combination and on which bits) to know how the loco would stop

On reflection, the handbrake would only brake the tender, so couldn’t have been used here (will edit). So the crew only had reverse gear, and the levelling of the gradient to eventually come to a stop.

They were lucky, especially the fireman, who could easily have gone through the gap and onto the track.

 

[MotCO]

Unless I am imagining it, wasn't there a case of a passenger train splitting between Victoria and Battersea Park, probably in the last 10 -15 years?

 

[stuving]

In 1958 Britannia 70014 detached from its tender at speed while hauling a passenger train, when the tender drawbar snapped. The loss of vacuum caused the tender and train brakes to apply and stop that portion, but the solo loco carried on as a runaway with the crew in a desperate situation. They had no control of the boiler and with the water supply severed, had to manually drop the fire to prevent a possible boiler explosion. Eventually the loco was brought to a stop, by the levelling gradient, and reversing gear.

In fact it was 1 a.m. on Thursday 27th January 1955. The press reports all stick close to the short text BR gave them, except this one, which adds something about the danger to the crew: The Rugeley Times; Saturday 29 January 1955; Page 3

ALARMING RAIL MISHAP AT ARMITAGE

When approaching Armitage station at 1 a.m. on Thursday an engine broke away from its coupling to the tender and coaches while travelling at 60 miles per hour. It was the northward bound Euston to Manchester express, pulled by a Brittania class engine.
The driver and fireman were in great danger of unbalancing from the footplate when the engine broke from the rest of the train. The locomotive could not be halted immediately as the brakes operate more efficiently when coupled to carriages.
It was not until two-and-a-quarter hours later that passengers could continue their journey from relief engine being brought from Stafford. Some of the other expresses held up by the mishap were diverted through Birmingham,
A temporary coupling for the engine and Its tender was made by a breakdown train crew from Stafford, and it was taken to the Stafford sheds for repair.

The main bit of detail that version omits is the stopping place of the bare loco, at Carwardine, 1½ miles on.

 

[Dr Hoo]

I sort of recall a separation between units (158s at Glasgow Queen Street?) that led to a rule that after coupling Sprinters the driver should attempt to drive one away with the brakes applied on the other. Presumably this can only be done after physical coupling but before the control circuits are connected.

Yes, that definitely happened. I remember (but didn’t witness it). They ran with the gangway doors locked for a while.