Are some trains too long?

[43066]

And this is why if I hear a suitcase being pushed against the cab door I refuse to move my train until it's been moved.

I once had someone removed from my train as they put their case back there as soon as we started moving.

We have similar issues, with bikes in particular. It’s always worth having a quick look through the cab doorway spy hole at station stops!

 

[bahnause]

Much of the energy consumed in moving a train is aerodynamic drag, which depends primarily on the frontal area - which is the same whether the train has two coaches or twelve.

This would be correct if the additional coaches or a second unit weighed 0. However, since this is not the case and the recuperation proportion remains the same regardless of the number of units, the energy expenditure roughly doubles when the number of units doubles.

 

[nw1]

Purely "enthusiast hat" comment, but : I will say that the lack of split and join arguably does make the operations of commuter railways less interesting than it used to be; the intricacies of matching allocations to demand was always one of the things that kept the South Western, for example, especially interesting in the latter days of BR and indeed much of the SWT era.

This did last well into the privatisation era, it wasn't just BR; certainly in the late 90s there were still plenty of 4-car units working services off-peak on SWT. Even in the Desiro era you'd have some 4-car 450s and certainly many 5-car 444s running out of Waterloo off-peak in the late 00s and early 10s.

It does appear it's still done in places, as evidenced by the comments on Epsom and Greater Anglia.

The other thing which makes the commuter railway of the 2020s so much less interesting to that of the 80s, 90s and 00s (and indeed the 50s, 60s and 70s before that) is the lower number of peak extras.

I don't want to start a discussion about the reasons behind all this, which I'm mostly aware of - just observing that the modern commuter railway is so much less interesting IMO.

I would agree that the Stansted Express is not the service to do it though!

 

[trebor79]

Sure the driver would have been very understanding of your blocking their only emergency exit!

Fair point.

 

[nw1]

Ten cars are necessary on the main line to Southampton and Bo9urnemouth, but the Weymouth electrifcation was done on the cheap, and can't supply power to operate ten-car trains (*), so five have to be detached at Bournemouth.

You used to also get splits at Southampton, which could cut down on the number of units required - with the rear unit sent back to London.

One example from December 2011 involved the 0740 down service splitting at Southampton Central, with the rear unit attached to the 1030 up service.

 

[AM9]

This would be correct if the additional coaches or a second unit weighed 0. However, since this is not the case and the recuperation proportion remains the same regardless of the number of units, the energy expenditure roughly doubles when the number of units doubles.

But in the overall picture, modern EMUs driven correctly can be fairly frugal on energy consumption, and its cost probably dwarfed by the additional movements involved in uncoupling, removing to stabling, retrieving from stabling and attching the stood down unit all of which requires additional labour including platform staff involvement. There's also the minor impact on the coupling interface (admittedly far less than days of old before Scharfenburg types were fitted). Even the failure of a unit's traction can be minimised by the other unit(s) providing rapidly available recovery capabilities. The 1.6MW of a modern 4 or 5-car unit is usually capable of dragging another along to avoid a loco rescue on a busy route. Even after the practice of TOC ppm charging has gone, delays will still be one of the largest reutational costs.

 

[Julia]

There are some Southeastern services in the middle of the day that are 10-cars which outside the peaks don't need to be, if space utilisation was the only consideration. However, I imagine there comes a point where the cost of chopping and changing formations regularly in the day costs as much as just allowing services to run in an excessively long formation (there's cost to ECS moves and extra drivers performing the extra moves, and station staff shutting down trains).

Plus extra delay costs. My commute home used to be an evening Kings Cross - Peterborough which would join 4x365 and 8x365 (can't remember which one was empty from HE), which at the time was one of the worst performers for punctuality as it would be late away whenever either inbound working was delayed, and when the units' autocouplers refused to play nicely together - which was surprisingly common. Ten minutes of faffing in the depot, nobody notices. Ten minutes extra platform occupation in the peak, everybody notices!

 

[bahnause]

But in the overall picture, modern EMUs driven correctly can be fairly frugal on energy consumption, and its cost probably dwarfed by the additional movements involved in uncoupling, removing to stabling, retrieving from stabling and attching the stood down unit all of which requires additional labour including platform staff involvement. There's also the minor impact on the coupling interface (admittedly far less than days of old before Scharfenburg types were fitted). Even the failure of a unit's traction can be minimised by the other unit(s) providing rapidly available recovery capabilities. The 1.6MW of a modern 4 or 5-car unit is usually capable of dragging another along to avoid a loco rescue on a busy route. Even after the practice of TOC ppm charging has gone, delays will still be one of the largest reutational costs.

The units also need maintenance. And breaks during the day are very suitable for this. Many vehicles that are not in use between rush hours are undergoing maintenance, exterior cleaning, interior cleaning or a combination of these elements. Spreading this work throughout the day ensures even utilisation of the maintenance facilities without having to provide additional capacity for the night.

 

[Magdalia]

Plus extra delay costs. My commute home used to be an evening Kings Cross - Peterborough which would join 4x365 and 8x365 (can't remember which one was empty from HE), which at the time was one of the worst performers for punctuality as it would be late away whenever either inbound working was delayed, and when the units' autocouplers refused to play nicely together - which was surprisingly common. Ten minutes of faffing in the depot, nobody notices. Ten minutes extra platform occupation in the peak, everybody notices!

Class 365s were notorious for this. There was a timetable when 1606 ex Ely arr 1730 joined with 1556 ex Kings Lynn arr 1733 to form 1745 back out to Kings Lynn. To make matters worse, this was booked to take place in platform 9, which had a kink almost exactly halfway along.

I always joined the country end, because of the number of times that the train eventually departed 10 minutes late as a 4 car.

And there was one famous incident where a Peterborough train did not join properly and came apart at high speed near New Southgate.

 

[AM9]

The units also need maintenance. And breaks during the day are very suitable for this. Many vehicles that are not in use between rush hours are undergoing maintenance, exterior cleaning, interior cleaning or a combination of these elements. Spreading this work throughout the day ensures even utilisation of the maintenance facilities without having to provide additional capacity for the night.

Pitch that against the comment by @Julia in post #73. I imagine trying to match individual train capacity against an expectation of it's passenger demand on that service is generally a fruitless practice given the organisational, mechanical reliability and overall service dealy issues that can arise might result in a minimal or even negative cost saving. The risk is that passengers will desert the service because of such a practice.

 

[Horizon22]

Are some trains too long for the demand of the particular service they are doing? Definitely. Get on a contra-peak service from a London terminal back to the outer destination mid-route at about 0930 and you'll wonder where everyone is!

However trains cannot teleport obviously and rail demand can be quite peaky, so what goes in, must go out and after doing A-B, whilst B-A might have low demand, A-B on the second trip might be reasonable. You could also send the train from A to C/D/E if it is more approriate. Of course some trains go to depots after peak, but there is still an off-peak timetable to satisfy.

Trying to accurately match demand always would be a) incredibly operational difficult (e.g. impossible), b) lead to extra risks and delays with swaps / attaching / joining c) unable to be resilient to any slight upticks in demand for any particular reason d) make the maintenance plan very fragile in the event of even minor disruption.

 

[Bletchleyite]

Trying to accurately match demand always would be a) incredibly operational difficult (e.g. impossible), b) lead to extra risks and delays with swaps / attaching / joining c) unable to be resilient to any slight upticks in demand for any particular reason.

It does sometimes happen, but for resilience reasons the newer WCML timetable has reduced it. But to use one example there's certainly a mid-evening arrival from Euston at New St (arrives around 2100, so busy northbound) that splits in two and does both the 2136 and 2206 back, both of which only need 4 cars.

Obviously you can't split a Pendolino in half, but no doubt EMR, with their 5 car 810s, will be doing some of what is described.

 

[Horizon22]

It does sometimes happen, but for resilience reasons the newer WCML timetable has reduced it. But to use one example there's certainly a mid-evening arrival from Euston at New St (arrives around 2100, so busy northbound) that splits in two and does both the 2136 and 2206 back, both of which only need 4 cars.

Obviously you can't split a Pendolino in half, but no doubt EMR, with their 5 car 810s, will be doing some of what is described.

Yes and I'm not saying that splitting / joining is not completely without merit in certain cases and will normally be part of the train plan for fleet that can do so.

But the suggestion was that some trains are too long and it's hard to say "No", but considering the bigger picture that is just something that will naturally happen on certain routes at certain times of day and thats completely fine. To try and be really particular will cause some of the problems I listed above. Way too fiddly, lacks resilience and a planning nightmare.

 

[Wilts Wanderer]

It’s probably also fair to say that splitting units is less prone to failure than joining them, so late-night working such as the example @Bletchleyite gives is more likely than the equivalent joining move early in the morning to allow the first trains to be tailored to demand.

I remember reading that Southern’s inter-peak policy was to leave suburban sets in their peak formations all day to protect the evening peak from fail-to-couple delays etc whereas South West Trains would routinely destrengthen between the peaks, and the delay statistics were noticeably different for the two operators. (I think it was that way round!)

 

[Bletchleyite]

It’s probably also fair to say that splitting units is less prone to failure than joining them, so late-night working such as the example @Bletchleyite gives is more likely than the equivalent joining move early in the morning to allow the first trains to be tailored to demand.

There did used to be a few evening peak 12-cars from Euston that were built up of incoming 4-car sets over a couple of hours. I don't think there are now - most stay 8 car all day and peak extras have been added rather than lengthening.

I suspect that this might change with the coming of the 730/2s though, as 10 car will be gross overkill on MKC stoppers during the day. Tring semi fasts will be interesting to see, 5 might be enough all day, peak included, if the peak extras remain.

Should probably mention - the masters of splitting and joining (for capacity rather than multiple destinations) are Chiltern, who do some impressive stuff with their very constrained fleet in terms of matching it to capacity, including on the fly. A couple of weeks back an extra unit was sent up from Aylesbury and coupled to the Vale Parkway-Marylebone service to get it to Marylebone without needing a dedicated driver, it was then split off there to work something else, presumably replacing a failure.

 

[norbitonflyer]

You used to also get splits at Southampton, which could cut down on the number of units required - with the rear unit sent back to London.

One example from December 2011 involved the 0740 down service splitting at Southampton Central, with the rear unit attached to the 1030 up service.

Yes, I think Southampton is the more common split point now, although the section to Bournemouth can deliver enough power for ten, as it was electrified to take REP/TC formations (a REP, with two power cars, had the same power as two 442s - indeed the very same motors, rercovered from the REPs)

== Doublepost prevention - post automatically merged: Monday at 16:56 ==

This would be correct if the additional coaches or a second unit weighed 0. However, since this is not the case and the recuperation proportion remains the same regardless of the number of units, the energy expenditure roughly doubles when the number of units doubles.

I did say most of the power is used in overcoming drag. Mass is most relevant whenn accelerating a train, or lifting it against gravity, but at constant speed on level track, drag is more significant)

== Doublepost prevention - post automatically merged: Monday at 16:59 ==

And there was one famous incident where a Peterborough train did not join properly and came apart at high speed near New Southgate.

I'vev heard of that happen with a pair of 117s. Only connected by the jumper cables. The rear unit must have had slightly more power (and better brakes) as the train didn't come apart until it braked for the first stop, and ripped out the jumper connections.

== Doublepost prevention - post automatically merged: Monday at 17:02 ==

Of course some trains go to depots after peak, but there is still an off-peak timetable to satisfy.

This is, or at least used to be, done. two 2x4 peak hour trains arrive at the terminus - one goes empty to depot for routime naintenance, the other is split into two four car trains to form the return workings of both incoming services (and vice versa in the afternoon)

== Doublepost prevention - post automatically merged: Monday at 17:07 ==

It’s probably also fair to say that splitting units is less prone to failure than joining them, so late-night working such as the example @Bletchleyite gives is more likely than the equivalent joining move early in the morning to allow the first trains to be tailored to demand.

I remember reading that Southern’s inter-peak policy was to leave suburban sets in their peak formations all day to protect the evening peak from fail-to-couple delays etc whereas South West Trains would routinely destrengthen between the peaks, and the delay statistics were noticeably different for the two operators. (I think it was that way round!)

I have also seen trains that are normally 4 car off peak run as 8 car in wintry conditions, to avoid coupling problems in the evening peak (also gives more shoes in contact with the rails so a better chance some of them can overcome the ice)

(Another thing I niticed was that REP/TC formations ran with the REP in the middle, instead of at the London end, in poor weather, to give the REP's better traction whichever way it was going. The summer formation always had the REP at the London end so that, when demand required, both TCs could go to Weymouth, but in the winter only one would do so anyway - the ETH index of a 33/1 wouldn't cope with both.

 

[dk1]

On a related note I was on a Stansted to Norwich service yesterday afternoon. 4 car 755. It was almost full leaving Stansted and there were people standing Cambridge to Ely.

Some conductors get very hot under the collar about blocking our access doors. Large cases will fit in the overhead racks. The Stadler fleet are excellent for that.

 

[Krokodil]

That incidentally makes me wonder about the decisions of other TOCs to order shorter units that often run coupled together. For example, you often see two coupled units running on HS1. Especially when you're talking High Speed services where about half the end carriage is out of bounds to passengers, that seems a huge waste of capacity at busy times compared to just running a fleet of all-10-car trains - and this discussion seems to indicate that the net benefits of splitting are at best marginal.

Voyagers are the most egregious example. A nine car voyager has roughly the same number seats than a seven car 80x (807=453 seats, 220+221=462). Then account for the lack of a gangway which prevents passengers from distributing themselves across the length of the train, the duplication in staffing roles and the duplication of equipment and facilities (particularly those gas-guzzlers underneath).

And this is why if I hear a suitcase being pushed against the cab door I refuse to move my train until it's been moved.

I once had someone removed from my train as they put their case back there as soon as we started moving.

Likewise I refuse to dispatch a train if I suspect that the driver's door is obstructed. There is a long list of collisions where the best course of action was "chuck the emergency brake in and get the hell out of the cab".

 

[Bald Rick]

Stansted Airport recovered very quickly after the pandemic and I think is now well above those days in terms of passenger numbers flying in/out.

Above, but not well above.

2019 was 28.1m, 2024 was 29.8m.

I don’t know what the proportion using the train was, though. Stansted wanted it to be 40% IIRC, but they are nowhere near that.

 

[Kilopylae]

A couple of weeks back an extra unit was sent up from Aylesbury and coupled to the Vale Parkway-Marylebone service to get it to Marylebone without needing a dedicated driver, it was then split off there to work something else, presumably replacing a failure.

That's very impressive. I was once (summer 2024 I believe?) on an Oxford–London that, in the course of being diverted via Aylesbury, picked up a stranded unit to take it back to Marylebone.

Above, but not well above.

2019 was 28.1m, 2024 was 29.8m.

I don’t know what the proportion using the train was, though. Stansted wanted it to be 40% IIRC, but they are nowhere near that.

I always use the train for Gatwick but I have to use the coach for Stansted. The Stansted Express just doesn't start early enough and is too expensive.

 

[dk1]

Above, but not well above.

2019 was 28.1m, 2024 was 29.8m.

I don’t know what the proportion using the train was, though. Stansted wanted it to be 40% IIRC, but they are nowhere near that.

Not sure but both GA and the DfT seem very happy with how things are going. So good to see how busy both the airport and the trains are becoming again.

== Doublepost prevention - post automatically merged: Monday at 21:12 ==

End of the day Ely area improvement needs to happen and half hourly to Stansted but are there paths south of Cambridge to achieve this. I've always thought the Breakland line could be much better utilised if it was improved but there much more improvements to be made elsewhere.

So much rests on certain pinch points. Unfortunately nothing is moving forward.

 

[43096]

I'vev heard of that happen with a pair of 117s. Only connected by the jumper cables. The rear unit must have had slightly more power (and better brakes) as the train didn't come apart until it braked for the first stop, and ripped out the jumper connections.

And brakepipes, presumably?

(Another thing I niticed was that REP/TC formations ran with the REP in the middle, instead of at the London end, in poor weather, to give the REP's better traction whichever way it was going. The summer formation always had the REP at the London end so that, when demand required, both TCs could go to Weymouth, but in the winter only one would do so anyway - the ETH index of a 33/1 wouldn't cope with both.

A 33 has an ETH index of 48, which would be more than capable of heating 8 Mark 1s (which is what an 8-TC formation is).

 

[Bald Rick]

Not sure but both GA and the DfT seem very happy with how things are going. So good to see how busy both the airport and the trains are becoming again.

It is responsible for a rather significant proportion of GA’s revenue…

 

[brad465]

Class 365s were notorious for this. There was a timetable when 1606 ex Ely arr 1730 joined with 1556 ex Kings Lynn arr 1733 to form 1745 back out to Kings Lynn. To make matters worse, this was booked to take place in platform 9, which had a kink almost exactly halfway along.

I always joined the country end, because of the number of times that the train eventually departed 10 minutes late as a 4 car.

And there was one famous incident where a Peterborough train did not join properly and came apart at high speed near New Southgate.

Is there a news' article and/or old RailUK thread about this incident?

 

[dk1]

It is responsible for a rather significant proportion of GA’s revenue…

It most certainly is and always has been.

 

[Bald Rick]

It most certainly is and always has been.

Not before 1991 it wasn’t!

But with nearly 10m passengers, and average fare well over a tenner, you can see how just this one route knocks the rest of GA into the shade.

 

[dk1]

Not before 1991 it wasn’t!

But with nearly 10m passengers, and average fare well over a tenner, you can see how just this one route knocks the rest of GA into the shade.

Before 1991 I don’t think GA was about then to worry about it. I was however and rode up front on one of the then brand new 322s. Intercity provided the catering host and we had revenue officers onboard for the five passengers travelling on this half hourly service. How times change.

 

[Nottingham59]

It is responsible for a rather significant proportion of GA’s revenue…

Stansted - Liverpool St is the ninth largest station-to-station flow in the country when measured in passenger-km.

 

[Magdalia]

Is there a news' article and/or old RailUK thread about this incident?

Not that I can find. I'm fairly sure that it was before the 2009 timetable change when the class 321s came in.

 

[trebor79]

Some conductors get very hot under the collar about blocking our access doors.

Yes I realise the error of doing that now.

Large cases will fit in the overhead racks. The Stadler fleet are excellent for that.

Unfortunately, these don't, I know because I tried to put them up there on our way out last week.