Locomotive Multiple Working

[WesternGiraffe]

Is it possible to run 2 locomotive hauled push pull sets in a single formation with both locomotives providing traction, or would the locomotive of the second set have to be shutdown / isolated?

Research seems to indicate that it's technically possible, but I cannot find anything to indicate if it's permissible, as I would think that such a formation would have to be treated differently to a standard DMU / EMU formation.

 

[dosxuk]

Do the HST sets not fit your description? And what about the 91/43 mixed sets in the early days of the ECML? Both logos were providing traction in that case.

 

[marsker]

I think that the OP was referring to the likes of 2 Cl 68+Mk5 sets being operated together in multiple. I suspect that software issues may well preclude this and, in any case, such matters as platform lengths may well make it undesireable.
In days gone by, the ScR did operate the Glasgow-Edinburgh shuttles wth a Cl 27 at either end of a Mk2 set fitted wth Blue Star connections and I'm sure I remember seeing one with a Cl 37 substituting, ISTR that the locos had to be modified so that a fire alarm the rear loco also sounded in the front. Of course with the Bournemouth electrification, the SR operated a "Mix'n'match" system with EMUs, Cl 33/1, Cl 73 and Cl 74s. There were certainly services where a Cl 33/1 with a 4TC trailer set from Salisbury coupled to an EMU from Southampton or Bournemouth for the onward run to Waterloo, all driven from the leading cab.This makes me think that there's nothing in the rules that prevent 2 loco hauled push-pull sets being coupled provided both were under the full control of the driver in the leading cab. It's very unlikely, though, for reasons stated above.

 

[boiledbeans2]

I regularly see double headed Class 90s on freight.

 

[Cheshire Scot]

In days gone by, the ScR did operate the Glasgow-Edinburgh shuttles wth a Cl 27 at either end of a Mk2 set fitted wth Blue Star connections and I'm sure I remember seeing one with a Cl 37 substituting, ISTR that the locos had to be modified so that a fire alarm the rear loco also sounded in the front.

In the early days class 37 substitutions were regular or occasionally a class 25. On at least one occasion I saw a working with cl 37 on each end. I understand all of these substitutions required the substitute loco(s) to also be be manned as they did not have the fire alarm mod.

 

[D365]

ISTR that the locos had to be modified so that a fire alarm the rear loco also sounded in the front.

This modification was also required when DRS Class 37s were operating ’top and tail’.

 

[david1212]

Would it have been possible to control a formation of 33/1 + 4TC + 4TC + 33/1 from the leading 33/1 even if the trailing one was manned for safety? What about 4TC + 33/1 + 4TC + 33/1 or 4TC + 33/1 + 33/1 + 4TC?

 

[JohnofWessex]

I believe I saw something about a train from Waterloo that split at Basingstoke with a 33 and 4TC heading to Salisbury & an EMU or two then heading off to Southampton

 

[Richard Scott]

There were top and tail 37s over Settle and Carlisle route many years back. Locos had modified fire systems on them.
Seen it many times in Germany with 218s either end of a train, both powering.

 

[43096]

Is it possible to run 2 locomotive hauled push pull sets in a single formation with both locomotives providing traction, or would the locomotive of the second set have to be shutdown / isolated?

Research seems to indicate that it's technically possible, but I cannot find anything to indicate if it's permissible, as I would think that such a formation would have to be treated differently to a standard DMU / EMU formation.

ÖBB routinely do this with coupled RailJet sets. I’ve also seen 1116+RailJet+1144+hauled stock all jumpered up and both locos powering.

 

[Wyrleybart]

I believe I saw something about a train from Waterloo that split at Basingstoke with a 33 and 4TC heading to Salisbury & an EMU or two then heading off to Southampton

Yes. IIRC is was the 1700 from Waterloo which split at Basingstoke, with the 4VEP carrying onto Southampton, then the Crompton pushing the TC to Salisbury.
It was on the list of my things to do which I never achieved.

This was of course made available by the (fairly) standard southern EPB system - the thumpers being slightly different I believe.

The formations in the question are achieved every day in Germasn and Austria with railjet trains formed of a cab car at one end and an electric loco on the other end. Timetabled joins and splits se these trains couple in multiple mo matter which end of the set of stock each loco is, which means it is possible to have two locos coupled together in the middle with a "cab car" at the outer ends.

 

[Richard Scott]

There were top and tail 37s over Settle and Carlisle route many years back. Locos had modified fire systems on them.
Seen it many times in Germany with 218s either end of a train, both powering.

Also seem to remember 73s working top and tail on the Clapham Junction to Kensington Olympia turn for a while with both locos powering.

 

[Harpo]

Early 1990s T&T 86s were discussed for Anglia when a DBSO shortage looked increasingly likely. Technically it was all deemed acceptable, including the OHLE, but drivability through neutral sections was the main reason for ruling it out.

 

[Taunton]

In days gone by, the ScR did operate the Glasgow-Edinburgh shuttles wth a Cl 27 at either end of a Mk2 set fitted wth Blue Star connections and I'm sure I remember seeing one with a Cl 37 substituting, ISTR that the locos had to be modified so that a fire alarm the rear loco also sounded in the front.

We have discussed this notable 1970s innovative service here before. There were several versions of the Class 27 "Push-Pull" fire alarm modification as various issues arose, having got it straight the later ETH variant in Class 27/2, with the Deutz auxiliary diesel engine just at one end started it all again, this noisy little unit also having a propensity to overheat or actually catch fire, with more than one of the modified locos being seriously damaged, and periods where the fireman, the locos still being traditionally manned, had to ride in the rear loco on eastbound journeys, as the ETH loco was always on the Glasgow end.

Issues with false fire warnings do seem to have been a continuing issue with multiple unit systems, another member here who lashed up more than the six allowed power cars combination of "Blue Square" traditional dmus wrote the first problem was the fire alarm going off. The issue with such key warning systems is they are dependent on always having a positive voltage to prove they are working, and MU wiring in lengthy formations can give rise to bad connections, or voltage drop outside the specification (which was one of the Class 27 issues). House burglar alarms which go off in a power cut show the same issue.

 

[norbitonflyer]

I believe I saw something about a train from Waterloo that split at Basingstoke with a 33 and 4TC heading to Salisbury & an EMU or two then heading off to Southampton

Indeed there were. I used themn a couple of times. Not sure if it could work with the loco at the rear though (although a TC+33 was of course possible)

== Doublepost prevention - post automatically merged: 8 Mar 2026 ==

Is it possible to run 2 locomotive hauled push pull sets in a single formation with both locomotives providing traction, or would the locomotive of the second set have to be shutdown / isolated?

Research seems to indicate that it's technically possible, but I cannot find anything to indicate if it's permissible, as I would think that such a formation would have to be treated differently to a standard DMU / EMU formation.

Certainly. here is an example. Note that both locos have their pantograghs raised.

 

[GRALISTAIR]

Also seem to remember 73s working top and tail on the Clapham Junction to Kensington Olympia turn for a while with both locos powering.

I remember that too.

 

[norbitonflyer]

Also seem to remember 73s working top and tail on the Clapham Junction to Kensington Olympia turn for a while with both locos powering.

Sometimes top and tail, sometimes both on one end. I seem to recall there had to be both a 73/0 and a 73/1. Something to do with neither being able to do both heating and MU control when on diesel power, so you needed one of each?

 

[Richard Scott]

Sometimes top and tail, sometimes both on one end. I seem to recall there had to be both a 73/0 and a 73/1. Something to do with neither being able to do both heating and MU control when on diesel power, so you needed one of each?

Definitely both 73/1 when I did it, was summer so no heat required.
73/0 could provide heat on diesel but not power at the same time.

 

[Sun Chariot]

I regularly see double headed Class 90s on freight.

That's great; but how does that fit the OPs question (and this thread) about one loco at each end of a (typically) passenger stock rake and with both locos simultaneously powering their train?

There were top and tail 37s over Settle and Carlisle route many years back. Locos had modified fire systems on them.

Oh that rings bells in my grey cells Can you recall roughly when?

I was thinking of the Fragonset 31s, one at either end of two Mk2 air-con carriages, briefly used between Bletchley and Bedford 1999/2000-ish. However, I'm certain the trailing 31 was merely dragged. I have a photo of them but they were stood still...

 

[bahnause]

Early 1990s T&T 86s were discussed for Anglia when a DBSO shortage looked increasingly likely. Technically it was all deemed acceptable, including the OHLE, but drivability through neutral sections was the main reason for ruling it out.

A few weeks ago, I drove a train with three locomotives. As the ETCS on the DVT (carriage 9) was defective, a Re460 was coupled in front of it as a substitute. A supplementary module comprising three carriages and an additional locomotive was then added in front of this locomotive. This did not affect the neutral sections.

 

[themiller]

A few weeks ago, I drove a train with three locomotives. As the ETCS on the DVT (carriage 9) was defective, a Re460 was coupled in front of it as a substitute. A supplementary module comprising three carriages and an additional locomotive was then added in front of this locomotive. This did not affect the neutral sections.

View attachment 199783

In Switzerland, mid-train helper locos were used on the mountain lines but they were discontinued some years ago in favour of bankers. Also, if you can think of a combination where the couplings are compatible, it’s probably happened there. For example, I’ve seen a night train exiting Olten with a second Re460 several coached from the from the leading one and shine clay trains over the Loetchberg used to have 2 locos at the front and 2 at the rear - all providing traction whilst ascending and regenerating on the south ramp.

 

[driver9000]

Oh that rings bells in my grey cells Can you recall roughly when?

Early 2000s when it was Arriva Trains Northern. They finished in 2004 just before the creation of the Serco-NedRail Northern franchise.

 

[Sun Chariot]

Early 2000s when it was Arriva Trains Northern. They finished in 2004 just before the creation of the Serco-NedRail Northern franchise.

Thanks, I must have seen a photo online around that time.

 

[Taunton]

In Switzerland, mid-train helper locos were used on the mountain lines but they were discontinued some years ago in favour of bankers.

Note that North America went the other way, where bankers (often multiple diesel formations themselves) had long been used they moved through inserting them at about the three-quarters point, then having them spread through the train ("distributed power"), and now do this everywhere, not just banking on gradients. The Locotrol remote radio system allows all to be controlled from the front cab. During the extensive development it was found that the "pull force" needed a neutral point between the sets of locos to avoid "string lining", that is pulling into derailment on curves..

I sometime see empty stone trains returning down the GWML, loco, full wagon set, another loco, another full wagon set. Not apparent how the second loco is controlled, or even if it is under power.

 

[WesternGiraffe]

Not really, both of those are fixed formations for the duration of the service they are operating. My interest lies in if you treat the 2 loco hauled sets like a DMU that could split en route.

Take a hypothetical TfW service that runs from Holyhead to Chester which comprises 2 class 68 + Mk 4 formations. At chester the service splits, with one half going to Cardiff and the other to Manchester. Where I have my interest is the stretch from Holyhead to Chester and that's where I was wondering if both 68's would be operational and providing traction.

 

[Harpo]

A few weeks ago, I drove a train with three locomotives. As the ETCS on the DVT (carriage 9) was defective, a Re460 was coupled in front of it as a substitute. A supplementary module comprising three carriages and an additional locomotive was then added in front of this locomotive. This did not affect the neutral sections.

View attachment 199783

The T & T 86s proposal wouldn’t have ‘affected’ the neutral sections but from a driveability viewpoint instead of just powering off a loco through the neutral before running-up again, the entire train would have had to do so introducing risks and difficulties which were deemed unacceptable.

Other types or nationalities of locos might not necessarily need to be driven the same way.

 

[bahnause]

The T & T 86s proposal wouldn’t have ‘affected’ the neutral sections but from a driveability viewpoint instead of just powering off a loco through the neutral before running-up again, the entire train would have had to do so introducing risks and difficulties which were deemed unacceptable.

Other types or nationalities of locos might not necessarily need to be driven the same way.

This is basically the same as it is here in Switzerland. Before reaching the neutral section, switch off the MCBs. When all pantographs have passed, switch the MCBs back on. For some neutral sections, it is necessary to lower the pantographs depenting on their position. Many modern trains have an automatic system that the train driver activates at the beginning of the neutral section. This system switches off the corresponding MCB depending on the position of the pantographs in the train or lowers the pantographs.

 

[Wyrleybart]

Not really, both of those are fixed formations for the duration of the service they are operating. My interest lies in if you treat the 2 loco hauled sets like a DMU that could split en route.

Take a hypothetical TfW service that runs from Holyhead to Chester which comprises 2 class 68 + Mk 4 formations. At chester the service splits, with one half going to Cardiff and the other to Manchester. Where I have my interest is the stretch from Holyhead to Chester and that's where I was wondering if both 68's would be operational and providing traction.

It all depends on the MU system being used I imagine. At the moment I believe TfW use the AAR system to control the class 67s from the DVT cabs, when the 67s are on the rear,

Not sure whether the TfW Mk4 MU was the same as the Mk3 fitment used by TfW and Chiltern. This also assumes the Chiltern modified class 68s (008-015) which are just ending service with the Chiltern Mk3s are actually able to work with the TfW Mk4s if they have the same AAR control system.

 

[156444]

I sometime see empty stone trains returning down the GWML, loco, full wagon set, another loco, another full wagon set. Not apparent how the second loco is controlled, or even if it is under power

The second loco isn't powered - they just run it like that to reduce the shunting needed at Wembley Yard when combining two trains

 

[Bevan Price]

In the early years of the Bournemouth line electrification, there were some (4TC+73+73+4TC) formations, with a driver in the front 4TC.