Why isn't EMU + Loco not used more for running over gaps in wired areas?

[renegademaster]

The only instance I know of the top of my head about now is the royal mail trains. I think I've seen a few times in the continent.
Surely it would be cheaper to have a few 67s sitting at uckfield han keeping two sets of stock like southern currently do

 

[HSTEd]

If we had a universal multiple unit control standard that allowed any train to be coupled to any other without issue, you might be correct.

But as it stands the cost of providing trained crew for the 67s, fueling them, maintaining them and the shunt moves, plus the disruption of coupling and uncoupling (and run arounds at the diesel terminus) would far exceed the costs of just buying some DMUs.

 

[stuu]

The only instance I know of the top of my head about now is the royal mail trains. I think I've seen a few times in the continent.
Surely it would be cheaper to have a few 67s sitting at uckfield han keeping two sets of stock like southern currently do

Hardly anywhere has the infrastructure to support locos attaching and detaching and getting out of the way etc, regardless of the actual costs and other practicalities HSTEd has already mentioned

 

[Fincra5]

The only instance I know of the top of my head about now is the royal mail trains. I think I've seen a few times in the continent.
Surely it would be cheaper to have a few 67s sitting at uckfield han keeping two sets of stock like southern currently do

Unfortunately the Railway doesn't work like it used to...

Even if you fitted a Dellner to a Class 67 it could drag a 377 (and keep air in the train) but unless it also has a MITRAC TMS fitted and a lot more modifications to both Loco and EMU, it wouldn't work the Brakes, Doors, Lighting, HVAC, etc.

Short answer. No.

 

[30907]

It was more common in the days before bi-modes (on the East Coast) and Voyagers on the West Coast - but not on short-distance routes like Uckfield, except in emergency.
I've not heard of mainland European examples involving EMUs except the TGV that used to run to Les Sables d'Olonne. Dragging loco-hauled trains is still common in CZ and SK, and no doubt elsewhere, but that's technically much simpler.

 

[ChiefPlanner]

Back in the day - when we had "one railway" - it was quite normal for 47's etc to drag WCML inter City sets with leccy via Coventry to Nuneaton when needed , and for example Bletchley to Bedford / St Pancras. (and no doubt other route sections)

Was it expensive - yes a bit , but there was a difference in keeping people off buses (or not travelling at all) - and a bit of overtime and flexibilty made a bit of a change to the mundality of your average Sunday. I do not recall any major issues with these "diverts" - though there was a block on over keen BY depot dragging 310 units to Bedford ,something to do with the triple valves on the units , so a local B==ing ensued and the practice ceased - but carefully gathered in DMU's kept buses at bay.....

Yes , I know there were less overall trains around etc.......people would rave now to see 87 / 90's in the St Pancras train shed.....

 

[Nick Ashwell]

Are there any diesel locos which are currently compatible with any EMUs? Without that I guess cost is the main issue as you aren't going to want barrier wagons.

I think Bi Mode locos like the 99 may make some services viable, but the cost of the locos and if it's less than Bi mode units when considering loco + coaches is going to be important here going forwards. All dependant on manufacture choices tbh

 

[Magdalia]

One of the main issues with modern trains is being able to open and close power operated doors.

In the days of slam door class 312s the GN outer suburban trains would be dragged quite frequently on Sundays when the overhead line (OHL) was isolated for maintenance. There were also a few instances of class 312s being dragged between Cambridge and Royston before the OHL was energised.

But that all ended when the class 317s took over.

Class 67s dragging class 91+MarkIV is much more recent: this was done on ECML diversions via Ely in 2019. But it is no longer necessary now that bimodes can be used.

 

[AngusH]

Lack of standards is the main problem.

If there were standards for TMS interoperability and standardised couplers a lot of useful things would be possible.

There is no unsolvable engineering reason why locomotives can't control multiple units and vice-versa.
Nor why different types of multiple unit can't work together.
(BR did both in the southern region!)

Except of course that it was not specified at the time of purchase and is now probably too late to retrofit.

(I can accept that cost might be an issue, but I can't find much to say that it was considered
and rejected on cost grounds)


the 317 thing is interesting because ISTR that the class 210 was intended to work in multiple with them
and I suppose would have given something that could work over gaps exactly as wanted here.
(I'm not sure if they ever did work as such though?)

 

[DaveyJones]

RSSB did some initial investigation into this, the problem is arguably worse still than when it was conducted

Electrical and Data Control Compatibility Between Trains (T1137)

This project investigates technical solutions for standardising couplers and data control compatibility between trains electrically as well as mechanically.

www.rssb.co.uk

 

[HSTEd]

RSSB did some initial investigation into this, the problem is arguably worse still than when it was conducted

Electrical and Data Control Compatibility Between Trains (T1137)

This project investigates technical solutions for standardising couplers and data control compatibility between trains electrically as well as mechanically.

www.rssb.co.uk

Ultimately this is going to get worse until RSSB actually bothers to define a standard and ORR/Government force people to comply with it.

But unfortunately, doing such a thing would require challenging vested interests in the rail industry and that's not something that happens in Britain any more.

Train manufacturers are strongly incentivised to create the maximum degree of "lock in" by specifying incompatible systems wherever possible.
Unless you end up wiht a powerful body, analogous to the AAR, forcing the issue they will never do it voluntarily.

 

[DaveyJones]

Oh Absolutely, if i recall correctly the project (above) concluded that it would potentially be better to develop a universal "control" system which connected Wirelessly rather than Mechanically. The Flaw there being that the associated "Mechanical Coupling Capacity" project found equally poor compatibility, but the convergence on usage of the Type10/12 was an improvement

 

[DJ_K666]

If we had a universal multiple unit control standard that allowed any train to be coupled to any other without issue, you might be correct.

But as it stands the cost of providing trained crew for the 67s, fueling them, maintaining them and the shunt moves, plus the disruption of coupling and uncoupling (and run arounds at the diesel terminus) would far exceed the costs of just buying some DMUs.

Southern Region style you mean? The class 33, 73 and 74 were all fitted with push-pull equipment which allowed the EMUs to be worked off the third rail by locomotives a la Bournemouth to Weymouth before it was electrified.

 

[HSTEd]

Southern Region style you mean? The class 33, 73 and 74 were all fitted with push-pull equipment which allowed the EMUs to be worked off the third rail by locomotives a la Bournemouth to Weymouth before it was electrified.

In essence yes, however despite the existence of several applicable standards the Government has not seen fit to ensure that one is adopted, which has resulted in the current mess.

Only government action to impose such a standard can clear this up.

 

[Krokodil]

Surely it would be cheaper to have a few 67s sitting at uckfield

Nothing involving a class 67 can be described as "cheap".

than keeping two sets of stock like southern currently do

Wouldn't a class 67 be a "second set of stock"?

Unless you end up wiht a powerful body, analogous to the AAR, forcing the issue they will never do it voluntarily.

It's the sort of thing that the Technical Standards for Interoperability ought to sort out.

 

[DJ_K666]

In essence yes, however despite the existence of several applicable standards the Government has not seen fit to ensure that one is adopted, which has resulted in the current mess.

Only government action to impose such a standard can clear this up.

Essentially everything using Dellner couplings plus compatible (or the same) software. With the Southern it was universal and mechanical couplings. Drop head buckeye couplers and either high level 'bagpipes' or standard air hoses

 

[HSTEd]

Essentially everything using Dellner couplings plus compatible (or the same) software. With the Southern it was universal and mechanical couplings. Drop head buckeye couplers and either high level 'bagpipes' or standard air hoses

There are several standards that could be used, including the standardised AAR ECP specification (that includes multiple unit control), the BR Mark 3 standard or any number of other ones.

But it would require the government to make the decision and force rolling stock procurement to stick to it.
Dellners would probably fit, especially as the EU is trying to get them adopted for freight operations, but tightlocks might be a better choice if the maintenance issue could be dealt with.

 

[Irascible]

The issue isn't the hardware though, is it - there's no defined software interface for TMS, and that's all of the problem ( electrical interfacing is well practiced at this point ). I don't know if the RSSB feel equipped to define a standard there, but they could at least host reps from manufacturers who know what to ask for. Cooperative working groups dealing with these precise issues, with commercial input are also ( very ) well practiced in the broader world of global networking world by now.

 

[DJ_K666]

There are several standards that could be used, including the standardised AAR ECP specification (that includes multiple unit control), the BR Mark 3 standard or any number of other ones.

But it would require the government to make the decision and force rolling stock procurement to stick to it.
Dellners would probably fit, especially as the EU is trying to get them adopted for freight operations, but tightlocks might be a better choice if the maintenance issue could be dealt with.

Yeah maybe. The government certainly should draft legislation and then give the industry an opportunity to adopt it voluntarily

 

[HSTEd]

The issue isn't the hardware though, is it - there's no defined software interface for TMS, and that's all of the problem ( electrical interfacing is well practiced at this point ). I don't know if the RSSB feel equipped to define a standard there, but they could at least host reps from manufacturers who know what to ask for. Cooperative working groups dealing with these precise issues, with commercial input are also ( very ) well practiced in the broader world of global networking world by now.

Ultimately, provided that the specification is properly implemented by all concerned, what TMS is being operated should not be a serious problem.

The AAR ECP standard is designed to operate with locomotives and freight vehicles from numerous manufacturers(APTA is now pushing it for passenger use), and the regular AAR multiple unit spec has endured for nearly a hundred years at this point.
I don't think asking manufacturers to lead the process is at all a good idea, since they have a vested interested in preventing the creation of such a specification that they would then be required to adhere to.

All the established players in this space can protect their market share by ensuring no such specification is ever developed, it's a huge conflict of interest.

 

[nw1]

Southern Region style you mean? The class 33, 73 and 74 were all fitted with push-pull equipment which allowed the EMUs to be worked off the third rail by locomotives a la Bournemouth to Weymouth before it was electrified.

Though it was generally not EMUs that worked to Weymouth, but unpowered 4TC units. Northeast of Bournemouth the 4REP EMUs would provide the power.

That said 33s could work with standard SR EMUs. I recall an occasion in January 1987 when my train home from school was a 33 hauling a 4VEP: heavy snow and extreme cold meant the EMUs could not negotiate the route on their own power.

There was also the famous Salisbury/Yeovil and Eastleigh/Bournemouth dividers, formed 33+TC (for Salisbury etc) and 8VEP (for Eastleigh etc), dividing at Basingstoke, with two such workings in the evening peak for much of the 80s (see many former nostalgia threads).

 

[Krokodil]

There are several standards

I know I'm taking this out of context, but there in four words is the problem.

Though it was generally not EMUs that worked to Weymouth, but unpowered 4TC units.

It's irrelevant. The important thing is that a locomotive could reliably haul, be controlled by, and provide ETS to a multiple unit. It proves the concept can work.

The big issue with Pendo drags (that probably put everyone off in favour of bi-modes for future procurement) is that neither unit or locomotive had really been designed outright for doing this on a regular basis. Nor could the unit control the locomotive so running round at Holyhead was necessary in addition to time-consuming shunt moves at Crewe on the Up to get the locomotive out of the way. Coupling up was unreliable, there were numerous problems, the unit was effectively dragged DIT for most functions.

If properly designed it would be no different to an 800 dragging an 801 (as I understand does happen on occasion). The locomotive is there waiting in the platform, the unit pulls in, couples up as units do up and down the country every day, the locomotive feeds ETS (probably known as Head End Power these days), and has full access to the functions of the unit's TMS. On the return the train arrives, locomotive is detached from the rear (again as you'd detach another unit), either leaving the loco in the platform for the next arrival or shunting it without delay to the train which can continue forward.

It works between units every day (yes, I know that coupling faults occasionally happen) so there is no fundamental reason that it couldn't be implemented for a loco/unit combination. Someone just has to specify it.

Unfortunately someone at the DfT saw the farce going on at Crewe, decided that all locomotives took ages to couple (something around 15 minutes was claimed), and the result was the "bi-mode" specified for the IET programme. Bi-modes do offer more flexibility and you can divert at very short notice, but that comes at a cost of carting around a load of diesel engines, paying Hitachi handsomely for the privilege.

 

[43096]

I don't think asking manufacturers to lead the process is at all a good idea, since they have a vested interested in preventing the creation of such a specification that they would then be required to adhere to.

All the established players in this space can protect their market share by ensuring no such specification is ever developed, it's a huge conflict of interest.

There's both risks and opportunities for the manufacturers, depending on how confident they are in their products. For every risk of another manufacturer selling trains into an existing customer, the boot is on the other foot elsewhere. Presumably GE and EMD were happy with the AAR approach for similar reasons. As an example, Candian Pacific at one point was almost entirely an EMD traction fleet, until GE's AC4400CW became CP's choice for AC traction - that change being made easier because they could run mixed formations thanks to the AAR standard.

 

[Dr Hoo]

I will presume that the 'loco hauling' would effectively be in push-pull mode, i.e. no run-rounds at each end to deal with the single-platform Uckfields of this world.

Quite apart from any loco modifications, such as for door control/detection, passenger alarms and so on, presumably there would have to be locomotive control systems in the EMU cab, e.g. for switching 'tail lamps', fire detection and even shut down/re-start in these emission-conscious times?

 

[HSTEd]

There's both risks and opportunities for the manufacturers, depending on how confident they are in their products. For every risk of another manufacturer selling trains into an existing customer, the boot is on the other foot elsewhere. Presumably GE and EMD were happy with the AAR approach for similar reasons.

I don't think whether they were happy or not was really a major factor.
Ultimately with the AAR standing behind the specification, they could either comply or not sell any locomotives to the member railroads. Apparently, the Union Pacific dissented for a while and stuck with an older Alco specification before eventually falling into line.

The standard dates from the 1940s so predates the explosive post WW2 growth in dieselisation. Notably it was also not the standard used by EMD, which was the dominant player in the diesel locomotive market at the time, it was derived from a GM specification.

A comparable situation would likely require the Government to select a specification and decree that no publically supported National Rail operator (so essentially all of them) would be permitted to purchase (or contract to lease) new equipment that did not comply with it.

 

[Trainbike46]

I don't think whether they were happy or not was really a major factor.
Ultimately with the AAR standing behind the specification, they could either comply or not sell any locomotives to the member railroads.

The standard dates from the 1940s so predates the explosive post WW2 growth in dieselisation. Notably it was also not the standard used by EMD, which was the dominant player in the diesel locomotive market at the time, it was derived from a GM specification.

A comparable situation would likely require the Government to select a specification and decree that no publically supported National Rail operator (so essentially all of them) would be permitted to purchase (or contract to lease) new equipment that did not comply with it.

And of course, the OAOs would follow suit, simply because the leasing companies would want to have the option of leasing the vehicles to a publicly supported operator if the OAO returns them or goes under. On top of that, most OAOs either operate trains that were previously operated by franchised operators, or use a design made for a government operator, so if the government operators start, the OAOs will follow

I do agree that improved interopability standards would be good, even if they aren't used for coupling locos to MUs, because they would be good for allowing different MU fleets to operate together, as sprinters and 170s already do

 

[StKeverne1497]

I know I'm taking this out of context, but there in four words is the problem.

I don't know how familiar people on Railforums are with the wonderful XKCD, but I offer here this little nugget from the pen of Randall Munroe:

If you go to the page where the image is posted, there is usually some mouseover text which is relevant too.

 

[zwk500]

The only instance I know of the top of my head about now is the royal mail trains. I think I've seen a few times in the continent.
Surely it would be cheaper to have a few 67s sitting at uckfield han keeping two sets of stock like southern currently do

1. Uckfield is currently a dead end single line so having a few 67s sitting there will just mean the units have to stop further up the platform (which is only just long enough for a 10-car which is the peak length).
2. The Uckfield line has some weak bridges, notably Oxted Viaduct, so locos are rather problematic.
3. Attaching and detaching locos takes time. Using the fleet of diesels means they can avoid all the operational costs of attaching and detaching locos at Oxted. Also Southern uses the diesels for Marshlink so some of the costs are shared across more units than just the Uckfield ones.

 

[Shaw S Hunter]

Unfortunately someone at the DfT saw the farce going on at Crewe, decided that all locomotives took ages to couple (something around 15 minutes was claimed), and the result was the "bi-mode" specified for the IET programme. Bi-modes do offer more flexibility and you can divert at very short notice, but that comes at a cost of carting around a load of diesel engines, paying Hitachi handsomely for the privilege.

This is a little simplistic. It's not just the time to (un)couple locos (which should be possible in rather less than 15 minutes), it's also the need to accommodate the associated light engine moves both in terms of pathing and crewing. The most likely places it would have occurred on the ECML routes were Edinburgh and Leeds, both of which are operated uncomfortably close to capacity at times. And the alternative to light engine moves would involve effectively abandoning the locos in the platform until the next service requiring them arrives, also a capacity killer. The whole argument is far from clear cut!

 

[ac6000cw]

I don't think whether they were happy or not was really a major factor.
Ultimately with the AAR standing behind the specification, they could either comply or not sell any locomotives to the member railroads. Apparently, the Union Pacific dissented for a while and stuck with an older Alco specification before eventually falling into line.

The standard dates from the 1940s so predates the explosive post WW2 growth in dieselisation. Notably it was also not the standard used by EMD, which was the dominant player in the diesel locomotive market at the time, it was derived from a GM specification.

AFAIK, the "AAR" MU control system was developed by GE originally, and became a de-facto standard because at the time GE supplied diesel loco electrical equipment to EMC/EMD and other builders. After EMD started making their own electrical equipment they carried on using the same MU system, and EMD's subsequent dominance of the US diesel loco market made it the obvious choice for the AAR to standardise on (and that took a long time, as there were some connector wiring variations between railroads).