Hull Trains Problems , Stock Problems

[ainsworth74]

But did they ever go there? Regular maintenance of 222s when with HT was carried out by Bombardier at Crofton, near Wakefield, scene of the 'oops we've dropped the train off the jacks' incident.

I would loved to have been a fly on the wall when Bombardier made the phone call to HT telling them that they'd dropped one of their trains. You just know that was an awkward conversation.

 

[Nym]

I would loved to have been a fly on the wall when Bombardier made the phone call to HT telling them that they'd dropped one of their trains. You just know that was an awkward conversation.

Most phone calls with Bombardier are awkward. Someone at work is actually seconded to work with them on testing, to make sure that the kit actually works...

 

[RAGNARØKR]

Which trains would these be? The 1937 LMS unit, with three coaches, each with an engine under the floor, used between 1937 and 1939 on those well-known short-distance routes between Oxford and Cambridge and St Pancras and Nottingham? Or the GWR units, again with engines under the floor of each coach, many of which were used between Birmingham and Cardiff, or the German Fliegender Hamburger sets, running between Berlin and Hamburg, etc, etc

My experience of early DMUs is of the streamlined single GWR railcars with a window behind the driver and an AEC bus engine under the floor and then the various BR Modernisation Scheme DMUs, with the BUT bus-type engine under the floor and used on short distance routes, and on that type of service they were adequate for the job. The longer distance diesels had trailer cars and I tended to go in those on the cople of times when I went on routes where they were running. Some of those sets had a GWR trailer in them, incidentally. Oxford to Cambridge was steam hauled until the Derby lightweights were introduced late in the 1950s. The LMS unit was an experimental one-off as you know. How did the public respond? The German units were for an exclusive high speed service and had engine compartments like the SNCF 4300 units. When the LNER suggested getting something similar, Gresley demonstrated that an A3 Pacific and ordinary coaches was more suitable for the railway's requirements that was the origin of the A4 Pacifics.

The GWR units built up the traffic to the point that 3-car sets came into service with a trailer centre car and if the traffic built up more then the service went back to steam haulage.

 

[sprinterguy]

HSTEd, all I can say is all this shaking must be an east coast phenomenon, as I simply don't recognise it as an issue on FGW 180s.

It's not something that I've noticed particularly on Grand Central's sets either. Perhaps I'm not looking hard enough to find fault...

 

[jimm]

My experience of early DMUs is of the streamlined single GWR railcars with a window behind the driver and an AEC bus engine under the floor and then the various BR Modernisation Scheme DMUs, with the BUT bus-type engine under the floor and used on short distance routes, and on that type of service they were adequate for the job. The longer distance diesels had trailer cars and I tended to go in those on the cople of times when I went on routes where they were running. Some of those sets had a GWR trailer in them, incidentally. Oxford to Cambridge was steam hauled until the Derby lightweights were introduced late in the 1950s. The LMS unit was an experimental one-off as you know. How did the public respond? The German units were for an exclusive high speed service and had engine compartments like the SNCF 4300 units. When the LNER suggested getting something similar, Gresley demonstrated that an A3 Pacific and ordinary coaches was more suitable for the railway's requirements that was the origin of the A4 Pacifics.

The GWR units built up the traffic to the point that 3-car sets came into service with a trailer centre car and if the traffic built up more then the service went back to steam haulage.

Not one word of which gets away from my original point that you remarking "pity about the underfloor engines" flew in the face of international design practice for diesel units from their earliest days.

Yes, there were some unpowered trailers in first generation dmus, but with the increasingly power-hungry designs of recent times, with air conditioning, power doors, etc, and the demand for better acceleration and performance overall, unpowered cars would not be practical now. There is a degree of redundancy built in, eg a 180 is meant to be able to perform on four engines pretty much as well as on five, but lose two engines and they struggle.

 

[RAGNARØKR]

Not one word of which gets away from my original point that you remarking "pity about the underfloor engines" flew in the face of international design practice for diesel units from their earliest days.

Yes, there were some unpowered trailers in first generation dmus, but with the increasingly power-hungry designs of recent times, with air conditioning, power doors, etc, and the demand for better acceleration and performance overall, unpowered cars would not be practical now.

In other words, DMUs are being used in applications which stretch the concept beyond its range of appropriate applicability.

And there were plenty of DMUs with engines in above-floor compartments eg the French and Swedish ones which are typical of the breed, with one powered car and one trailer.

Yes, you lose space but it is easier to maintain the engine when it is not under the floor, and easier to isolate the sound and vibration.

With the power hunger that you are describing, surely the obvious place to generate it is in a dedicated vehicle? This does not preclude building in the redundancy that we agree is desirable. The TRAXX DE adopts precisely this principle with four engines, presumably a mass-produced item that can be swapped out easily for repair on a workshop bench.

 

[jimm]

In other words, DMUs are being used in applications which stretch the concept beyond its range of appropriate applicability.

And there were plenty of DMUs with engines in above-floor compartments eg the French and Swedish ones which are typical of the breed, with one powered car and one trailer.

Yes, you lose space but it is easier to maintain the engine when it is not under the floor, and easier to isolate the sound and vibration.

With the power hunger that you are describing, surely the obvious place to generate it is in a dedicated vehicle? This does not preclude building in the redundancy that we agree is desirable. The TRAXX DE adopts precisely this principle with four engines, presumably a mass-produced item that can be swapped out easily for repair on a workshop bench.

But there's a very obvious problem with having a lump of iron above the floor, one which is apparently a terrible problem with diesel units, if I am to believe some people - no through corridor and no corridor connections.

And sitting in a coach with a diesel engine for company, wherever it is fixed, is always going to cause noise and vibrations. The units you have posted pictures of are old designs. More recent trains in Sweden and France have underfloor engines - and plentiful? Hardly. Not by comparison with numbers of underfloor-engined sets built way back when for BR and DB, and many other railways.

So where we've gone wrong is not building locos to operate local stopping services, as well as everything else, is it?

 

[RAGNARØKR]

But there's a very obvious problem with having a lump of iron above the floor, one which is apparently a terrible problem with diesel units, if I am to believe some people - no through corridor and no corridor connections.

And sitting in a coach with a diesel engine for company, wherever it is fixed, is always going to cause noise and vibrations. The units you have posted pictures of are old designs. More recent trains in Sweden and France have underfloor engines - and plentiful? Hardly. Not by comparison with numbers of underfloor-engined sets built way back when for BR and DB, and many other railways.

So where we've gone wrong is not building locos to operate local stopping services, as well as everything else, is it?

It would be if the local stopping services is a journey of several hours and the trains are above that generally agreed break-even point of around six cars. That is a lot of engines to maintain. I wonder where those who are responsible for maintaining the engines prefer them to be located?

 

[junglejames]

Not one word of which gets away from my original point that you remarking "pity about the underfloor engines" flew in the face of international design practice for diesel units from their earliest days.

Yes, there were some unpowered trailers in first generation dmus, but with the increasingly power-hungry designs of recent times, with air conditioning, power doors, etc, and the demand for better acceleration and performance overall, unpowered cars would not be practical now. There is a degree of redundancy built in, eg a 180 is meant to be able to perform on four engines pretty much as well as on five, but lose two engines and they struggle.

Im lost as to what the problem is with the quote- "Pity about the underfloor engines".

Underfloor engines are intrusive. Always have been, and for long distance highspeed services, they are a massive let down over conventional unpowered coaches. In fact, we should not be using underfloor engines on such services. The slightly better acceleration (remember voyagers and 180s only have such fantastic acceleration because they are horrendously overpowered) is not necessary on long distance services, and they are less efficient than HSTs or conventional LHCS.

So the quote seems a very natural quote. Yet it seems to have turned into an argument.

 

[HSTEd]

Im lost as to what the problem is with the quote- "Pity about the underfloor engines".

Underfloor engines are intrusive. Always have been, and for long distance highspeed services, they are a massive let down over conventional unpowered coaches. In fact, we should not be using underfloor engines on such services. The slightly better acceleration (remember voyagers and 180s only have such fantastic acceleration because they are horrendously overpowered) is not necessary on long distance services, and they are less efficient than HSTs or conventional LHCS.

So the quote seems a very natural quote. Yet it seems to have turned into an argument.

The only reason DMUs like Voyagers and Class 180s are less efficient than loco hauled formations is because they are ridiculously overpowered, if they were not they would be more efficient because they don't have to lug around a load of dead weight in teh form of the locomotive.

 

[Lewisham2221]

Surely something is not "overpowered" if it makes reasonable use of the power that it has. So a 220/180 making use of available power to give rapid acceleration, thus providing benefits of improved journey times and better pathing is arguably not "overpowered".

 

[dstrat]

Indeed also, in the light of how many times engines fail on these trains, which I understand to be be quite often, probably needs to be overpowered if that is the case.

 

[sprinterguy]

Indeed also, in the light of how many times engines fail on these trains, which I understand to be be quite often, probably needs to be overpowered if that is the case.

The common practice is to downrate engines to increase their reliability though, rather than an excess of power being a good thing for reliability.

Also, the class 180 Adelantes use the same Cummins QSK19 engines as the class 220/221 Voyagers and class 222 Meridians. The Voyagers and the Meridians win awards for the large number of miles between failures that they achieve and their excellent reliability overall. It is not the power units that are at fault on the 180s, it is other components, such as the hydraulic transmission system and the tendency for the trains to leak oil onto hot underfloor components.

 

[RAGNARØKR]

The only reason DMUs like Voyagers and Class 180s are less efficient than loco hauled formations is because they are ridiculously overpowered, if they were not they would be more efficient because they don't have to lug around a load of dead weight in teh form of the locomotive.

An earlier poster pointed out that energy costs are trivial in the overall scheme of things. But engines and transmissions under the floor add to the mass of each vehicle, and there comes a break-even point. There are also more engines to be maintained, fuel tanks to be topped up, coolant levels to be checked, etc, etc. Redundancy in a locomotive can be easily achieved as in the latest TRAXX locomotives with four engines, which in my opinion is over the top but the proof of the putting will be in the eating. If small mass-produced engines are easily swapped-out for maintenance in comfort on a workshop bench, that sounds like a good design stratagy.

 

[DarloRich]

Which could be part of the problem, then. No criticism of OOC but it a detour to get the trains there so perhaps they do not visit as often as they need to.

Old Oak Common is by far and away the best place to have the 180's maintained? Why? Becasue all the knowledge dealing with those trains is based there.

it is short journey form Kings Cross to OOC and iam sure the trains get serviced when they need it.

I THINK they are fed and watered at Alexander Palace

 

[Yew]

The only reason DMUs like Voyagers and Class 180s are less efficient than loco hauled formations is because they are ridiculously overpowered, if they were not they would be more efficient because they don't have to lug around a load of dead weight in teh form of the locomotive.

nstead they have to carry around 5-9 engines, all their anciliraies, strengthened carriages and such. Would they still have higher acceleration if they had similar power to a hst?



Not saying that there isnt a place for MU's but once you start running for 5 hours at high speeds, their acceleration advantages start to look bad compared to their fuel and maintainance costs, never minding the noise.

I've got to say though, EMU's are the way forward, especially if every axle is powered with a low noise motor. I'm just not convinced in IC DMU's The original IEP suggestion was alright, with a generator car to power the EMU motors, but I think the current suggestion is a step downhill.

 

[ainsworth74]

Not saying that there isnt a place for MU's but once you start running for 5 hours at high speeds, their acceleration advantages start to look bad compared to their fuel and maintainance costs, never minding the noise.

But of course they don't run for five hours at high speed. For example on XC apart from the extreme ends of the SW-Scotland set of services (beyond Bristol and Newcastle) there are stops roughly every twenty/thirty minutes.

 

[HSTEd]

nstead they have to carry around 5-9 engines, all their anciliraies, strengthened carriages and such. Would they still have higher acceleration if they had similar power to a hst?

Yes, in the low speed range the acceleration would be improved by having a greater percentage of the train on the driven axles.

Not saying that there isnt a place for MU's but once you start running for 5 hours at high speeds, their acceleration advantages start to look bad compared to their fuel and maintainance costs, never minding the noise.

You can't swap out a 3000hp diesel engine using a man assist and fix it on a workbench, you need to either use a crane of service/repair it mounted to teh train.

With MUs you can potentially remove the engine like Deltics did, but which is impractical with single plants these days. (Engines these days are heavier to get better fuel efficiency, trending towards lower rpm ranges and even Deltics had two engines).

An earlier poster pointed out that energy costs are trivial in the overall scheme of things. But engines and transmissions under the floor add to the mass of each vehicle, and there comes a break-even point. There are also more engines to be maintained, fuel tanks to be topped up, coolant levels to be checked, etc, etc. Redundancy in a locomotive can be easily achieved as in the latest TRAXX locomotives with four engines, which in my opinion is over the top but the proof of the putting will be in the eating. If small mass-produced engines are easily swapped-out for maintenance in comfort on a workshop bench, that sounds like a good design stratagy.

But then you loose any percieved maintenance advantage (that may not exist in the first place) but don't gain any of the benefits MUs have in terms of reduced axle loadings and weight.

The traction critical equipment in a Voyager weighs something like 15t, I doubt you could operate a practical four car loco hauled formation with a locomotive that weighs in at 15t.

And I don't think a loco hauled 125mph capable formation will have a route availability rating of RA2.

 

[RAGNARØKR]

You can't swap out a 3000hp diesel engine using a man assist and fix it on a workbench, you need to either use a crane of service/repair it mounted to teh train.

With MUs you can potentially remove the engine like Deltics did, but which is impractical with single plants these days. (Engines these days are heavier to get better fuel efficiency, trending towards lower rpm ranges and even Deltics had two engines).

But then you loose any percieved maintenance advantage (that may not exist in the first place) but don't gain any of the benefits MUs have in terms of reduced axle loadings and weight.

The traction critical equipment in a Voyager weighs something like 15t, I doubt you could operate a practical four car loco hauled formation with a locomotive that weighs in at 15t.

And I don't think a loco hauled 125mph capable formation will have a route availability rating of RA2.

The latest TRAXX diesel locomotive has four Caterpillar engines, which sounds odd on the face of things but presumably it is a standard automotive product.

How do you work out that Voyager traction equipment is 15 tones per unit? If I recall, the intermediate vehicles weigh 44 tons. Pesumably they would weigh around 36 as trailers, which makes about 8 tons or 72 per 4 car unit and 80 for a five-set.

 

[HSTEd]

How do you work out that Voyager traction equipment is 15 tones per unit? If I recall, the intermediate vehicles weigh 44 tons. Pesumably they would weigh around 36 as trailers, which makes about 8 tons or 72 per 4 car unit and 80 for a five-set.

What?

Even if we assume a 36t vehicle would be feasible with modern crash standards, that would mean they were 8t overweight which translates to 32t for a 4 set and 64 for an 8 car unit.

You won't get significantly under 40t for a new build trailer vehicle, even the Mark 4 didn't manage that, and many of the Mark 3s are like that based on the tare weights listed on many coaches in HST formations that I have seen.

 

[RAGNARØKR]

What?

Even if we assume a 36t vehicle would be feasible with modern crash standards, that would mean they were 8t overweight which translates to 32t for a 4 set and 64 for an 8 car unit.

You won't get significantly under 40t for a new build trailer vehicle, even the Mark 4 didn't manage that, and many of the Mark 3s are like that based on the tare weights listed on many coaches in HST formations that I have seen.

Somebody must know the weight of this kit down to the last kilo. It may be that the Voyager bodyshell is overweight. Mark 4 certainly are. The reason they are heavier than mark 3 is that the use of metal is less efficient. Mark 3 was pared down to the bare minimum but added to complexity of construction. There is no reason to assume that crashworthiness should add significantly to weight. It is mostly about putting the metal in the right place for the most foreseeable eventualities.

 

[HSTEd]

Somebody must know the weight of this kit down to the last kilo. It may be that the Voyager bodyshell is overweight. Mark 4 certainly are. The reason they are heavier than mark 3 is that the use of metal is less efficient. Mark 3 was pared down to the bare minimum but added to complexity of construction. There is no reason to assume that crashworthiness should add significantly to weight. It is mostly about putting the metal in the right place for the most foreseeable eventualities.

I can tell you the "wet" weight of a QSK-19 down to the last kilo (atleast what Cummins says it is in the relevant documentation available on their website), that is 1891kg.

I would expect roughly 500kg each for the generator and traction motor equipment and then a couple of hundred kilos for the traction control electronics.

Which takes us to about 3t for the entire rig excluding fuel.
Total fuel load will be about a 600-700kg per carriage.

So less than four tonnes for traction equipment including full fuel.

And with regards to structural strengthening to hold the weight, clever designs can use the rigidity of the engine block (it is after all a big block of metal) to reduce the loads on the carriage's structure.
So that is not really a massive factor, additionally modern designs can locate the traction motors entirely within the bogies (see the AGV).

 

[junglejames]

The only reason DMUs like Voyagers and Class 180s are less efficient than loco hauled formations is because they are ridiculously overpowered, if they were not they would be more efficient because they don't have to lug around a load of dead weight in teh form of the locomotive.

Incorrect. A load of small engines will always be less efficient than 1 large engine. You are on about the dead weight of the loco. But have you taken into consideration the extra weight of the coaches, and the extra weight caused by having everything in multiple? The numerous small engines will be heavier than 1 large engine. The numerous fuel tanks will be heavier. The extra transmissions will be heavier. The cabs will make the coaches heavier.
In the end you will find all this extra dead weight you mention is equal to less than the skin of the loco.

Sorry, but numerous engines will never be more efficient than 1 large comparable engine.

A voyager with the same power output as a loco wouldnt have much better acceleration than the LHCS formation, but would be less efficient.
Reason it wouldnt have much better acceleration? Because despite having powered axles spread throughout the train, giving slightly better acceleration at low speed, this is balanced out by the fact the voyager would have less power at the rail (more engines and transmissions means a higher percentage of engine power will be lost).

 

[RAGNARØKR]

Incorrect. A load of small engines will always be less efficient than 1 large engine.

Sorry, but numerous engines will never be more efficient than 1 large comparable engine.

What is the efficiency of a large railway/marine diesel engine compared to a small bus/truck one?

I understand that there was at one time a difference due to the differing efficiency of combustion in different sized cylinders but cannot remember which way round it was.

There are other factors too, such as the possibility of shutting down some of the engines when full power is not required whilst keeping the remainder on optimum power output. Perhaps the TRAXX multi-engine loco gets the best of both worlds?

 

[HSTEd]

Incorrect. A load of small engines will always be less efficient than 1 large engine. You are on about the dead weight of the loco. But have you taken into consideration the extra weight of the coaches, and the extra weight caused by having everything in multiple? The numerous small engines will be heavier than 1 large engine. The numerous fuel tanks will be heavier. The extra transmissions will be heavier. The cabs will make the coaches heavier.
In the end you will find all this extra dead weight you mention is equal to less than the skin of the loco.

Sorry, but numerous engines will never be more efficient than 1 large comparable engine.

Actually no.
As numerous studies have shown the duty factor of the power plant of a passenger train is rather low.
It tends to have bursts of lots of power but spends most of its time at relatively low settings if not idle.

A large power plant will burn huge amounts of fuel at idle, like in a platform to maintain hotel loads, whereas an array of smaller engiens can turn off engines and run the engines at the optimum point on the load curve (usually nearer flat out than idle) to reduce overall fuel consumption.

You mention the superior fuel consumption of larger engines versus smaller ones, this used to be a major factor but the difference has shrunk markedly in recent years with advances in CAD and similar technologies which have made engine designs overall more efficient.

Additionally alternator and motor weights do not scale linearly with power output, smaller motors and alternators can make use of cruder and lighter cooling technologies including no cooling at all in the latest permenant magnet designs.
3MW scale alternators require water cooling equipment with all the extra auxiliary loads and weight neccesary to support it.

The weight of a fuel tank is purely marginal, and indeed smaller tanks do not require as much weight diverted to internal baffles to prevent axial sloshing which can have various deleterious effects in the very large tanks seen on locomotives.

I am not entirely sure why a locomotive hauled formation with two cabs (single ended locomotive) would have less weight in cabs than a fixed formation multiple unit with.... two cabs.

As to the only extra weight in a locomotive being its "skin".... if that was the case you would have a locomotive that weighs in at something on order of 35-40t.
This is hardly going to generate the tractive effort a Voyager can where each vehicle has more than 20t on driven axles.
The engine block and generator casing and similar equipment can actually be made to provide additional rigidity and support to the bodyshell, allowing the increase in structural weight to be near zero, and in some cases possibly even negative.
(not much more rigid than the big block of metal that is an engine block).

A voyager with the same power output as a loco wouldnt have much better acceleration than the LHCS formation, but would be less efficient.
Reason it wouldnt have much better acceleration? Because despite having powered axles spread throughout the train, giving slightly better acceleration at low speed, this is balanced out by the fact the voyager would have less power at the rail (more engines and transmissions means a higher percentage of engine power will be lost).

No it won't, it will be far more efficient as you will have to move 30t or more of dead weight around with the locomotive in order to give it sufficient tractive effort to actually move the train up hills.

And the Voyager would have comparable power at rail (transmission efficiency no longer scales strongly with size, the rise of the power transistor has seen to that) and it would be more efficient thanks to being lighter and having the ability to turn off most of its engines when they are not required.
Whereas a loco hauled formation always has one engine running and thus cannot tailor its active power to optimise the engine's position on the load curve.

 

[RAGNARØKR]

Actually no.
As numerous studies have shown the duty factor of the power plant of a passenger train is rather low.
It tends to have bursts of lots of power but spends most of its time at relatively low settings if not idle.

A large power plant will burn huge amounts of fuel at idle, like in a platform to maintain hotel loads, whereas an array of smaller engiens can turn off engines and run the engines at the optimum point on the load curve (usually nearer flat out than idle) to reduce overall fuel consumption.

You mention the superior fuel consumption of larger engines versus smaller ones, this used to be a major factor but the difference has shrunk markedly in recent years with advances in CAD and similar technologies which have made engine designs overall more efficient.

Additionally alternator and motor weights do not scale linearly with power output, smaller motors and alternators can make use of cruder and lighter cooling technologies including no cooling at all in the latest permenant magnet designs.
3MW scale alternators require water cooling equipment with all the extra auxiliary loads and weight neccesary to support it.

The weight of a fuel tank is purely marginal, and indeed smaller tanks do not require as much weight diverted to internal baffles to prevent axial sloshing which can have various deleterious effects in the very large tanks seen on locomotives.

I am not entirely sure why a locomotive hauled formation with two cabs (single ended locomotive) would have less weight in cabs than a fixed formation multiple unit with.... two cabs.

No it won't, it will be far more efficient as you will have to move 30t or more of dead weight around with the locomotive in order to give it sufficient tractive effort to actually move the train up hills.

And the Voyager would have comparable power at rail (transmission efficiency no longer scales strongly with size, the rise of the power transistor has seen to that) and it would be more efficient thanks to being lighter and having the ability to turn off most of its engines when they are not required.
Whereas a loco hauled formation always has one engine running and thus cannot tailor its active power to optimise the engine's position on the load curve.

Most of the advantages of the multi-engined DMU also apply to the TRAXX multi-engined locomotive. But on another thread, it was stated that fuel consumption is a relatively small cost, and 30 tons is not much in the overall mass of a train.

As the Arup Value for Money study pointed out, the big costs are infrastructure, followed by staff and rolling stock. And the major cost of rolling stock it its capital cost. So it makes sense to keep it going for as long as possible. If traction is built into every vehicle, it will add at least 50% to the capital cost and will make it go obsolete sooner, as technical improvements come along. The hauled vehicles, on the other hand, just need a power supply for the lights and HV, and compatible braking systems to keep them rolling for decades.

Having all vehicles powered also leads to the recurring complaints about noise and vibration, which are certainly not solved in the Voyagers and class 180, where the presence of a large and powerful engine makes a solution difficult.

This discussion is interesting as it illustrates a widespread phenomenon. A traction system may have a high efficiency in theory but not in service conditions, and that efficiency may be bought at a cost that means it is not value for money.

 

[jonhewes]

This is an interesting debate, and I'm not sure which side of the fence I sit on with regard to the Loco-hauled vs MU debate. The

In an environment where passenger and freight services are operated by the same organisation, there would possibly be an operational advantage in having locomotives over MUs.

DB Regio are extensive users of Traxx Electric locos and have also ordered some multi engined Traxx Diesel locos for regional passenger services. In my eyes this is a rather odd choice, bearing in mind that (to my knowledge), there is no inter-operation between passenger and freight. These locos will be used exclusively on passenger services, which could in theory be operated by multiple units.

OBB (Austrian Railway) is quite an interesting case. Their Taurus (Electric) and Hercules (Diesel) locos are used universally for passenger and freight workings.

 

[RAGNARØKR]

This is an interesting debate, and I'm not sure which side of the fence I sit on with regard to the Loco-hauled vs MU debate. The

In an environment where passenger and freight services are operated by the same organisation, there would possibly be an operational advantage in having locomotives over MUs.

DB Regio are extensive users of Traxx Electric locos and have also ordered some multi engined Traxx Diesel locos for regional passenger services. In my eyes this is a rather odd choice, bearing in mind that (to my knowledge), there is no inter-operation between passenger and freight. These locos will be used exclusively on passenger services, which could in theory be operated by multiple units.

OBB (Austrian Railway) is quite an interesting case. Their Taurus (Electric) and Hercules (Diesel) locos are used universally for passenger and freight workings.

DB and DSB have fleets of 5-car double-deck trailer sets working in push-pull mode.