Steam Multiple Units..?

[Manchester77]

Right didn't know where to put this thread but was there ever any kind of steam multiple unit built? I'd guess the engines weren't underfloor but like two big cabs at the front with boilers etc but was such a beast ever built?
Thankyou!

 

[jopsuk]

There's the likes of Steam Railmotors- single carriage units, one of which has recently been restored to operational status and has been out on the Looe Branchline

There were also driving coaches that could be used with tank engines- eg two coaches sandwiching a locomotive. I think some of these were able to be used with steam rail motors

 

[Manchester77]

GWR's auto coach acted kinda like a DVT by the looks of things.
Thank you

 

[sprinterguy]

There's the likes of Steam Railmotors- single carriage units, one of which has recently been restored to operational status and has been out on the Looe Branchline
Once you look into it a bit, there were a surprisingly high number of steam railcars in use around the country at one time, and not just with the GWR. The LNER, for instance, had it's well known fleet of "Sentinel" steam railcars.

To provide a little bit more info for Manchester 77's query, steam railcars usually had a boiler at one end of the carriage that powered a four-wheel "power bogie" - Essentially a very compact 0-4-0 steam engine. The boilers used could be either vertical or conventional.

There were also driving coaches that could be used with tank engines- eg two coaches sandwiching a locomotive. I think some of these were able to be used with steam rail motors

The Autocoaches could be used up to a maximum length of two carriages each side of the locomotive if needed.

 

[Metrailway]

At Quainton Road, there is a Sentinal - Cammel steam railcar built in the 50s for the Egyptian National Railways.

 

[Buttsy]

At Quainton Road, there is a Sentinal - Cammel steam railcar built in the 50s for the Egyptian National Railways.

Though this was fuelled by diesel rather than coal.

 

[yorksrob]

The Southern Railway used to run a lot of push-pull units with a loco at one end and drivers cab at the other. Particularly handy for branchlines.

 

[Anon Mouse]

The GNR and later LNER used to have something that could have been called a SMU;

http://www.lner.info/locos/Railcar/railcar.shtml

http://www.lner.info/locos/Railcar/gnr_railmotor.shtml

http://www.lner.info/locos/Railcar/sentinel.shtml

http://www.lner.info/locos/Railcar/clayton.shtml

 

[6Gman]

But surely the key point here is that the steam railmotors operated one at a time - so to speak - so were not multiple units?

I've certainly never heard of them operating in pairs or trios.

 

[Anon Mouse]

But surely the key point here is that the steam railmotors operated one at a time - so to speak - so were not multiple units?

I've certainly never heard of them operating in pairs or trios.

What would you call a class 139? Even if not 100% correct do we collectivley call all railcars multiple units? That 'thing' at Quainton Road could definatly be called an SMU at least!

 

[RAGNARØKR]

What would you call a class 139? Even if not 100% correct do we collectivley call all railcars multiple units? That 'thing' at Quainton Road could definatly be called an SMU at least!

There were Great Western units with four cars ie

Driving trailer+trailer+1400 class loco+trailer+driving trailer.

The last of the driving trailers were post war and were named after birds. They were very comfortable, much more so than the DMUs which replaced them.

 

[Kali]

Sentinels were a little different, usually geared steam engines rather than direct drive. There were a couple of railmotors with steam power bogies also iirc ( basically a small steam engine where a traction motor would go ). You couldn't drive them in multiple, for starters someone has to fire & water the thing...

Autotrailers controlled the regulator & train brake, the fireman had to operate the reverser which is technically a driver's control. There were a lot built with pass-through control, not just GWR ones.

 

[Penmorfa]

What would you call a class 139? Even if not 100% correct do we collectivley call all railcars multiple units? That 'thing' at Quainton Road could definatly be called an SMU at least!

Would a 139 be a railbus?

The Egyptian one is fuelled by diesel so it's still a DMU

 

[asylumxl]

Would a 139 be a railbus?

The Egyptian one is fuelled by diesel so it's still a DMU

"Steam engines" are powered by coal. Does that make them Coal Locomotives?

 

[caliwag]

Those steam sentinels of the LNER were exceptionally reliable after some adjustment for smoke ingress...the LNER site is superb.

They also had brilliant names, apparently named after stage coaches...'Brilliant', 'Waterwitch', TrueBlue'. 'Neptune', Teagle', Woodpecker'. Umpire', and 'highland chieftain' Excellent stuff aye?

 

[DXMachina]

Would a 139 be a railbus?

The Egyptian one is fuelled by diesel so it's still a DMU

No, in your terminology it is an OMU (oil-fired) (although actually its not multiple-capable therefore is a multi car railcar). Diesel power requires an internal combustion engine ignited by compression. Also diesel fuel is just paraffin really....

 

[Penmorfa]

"Steam engines" are powered by coal. Does that make them Coal Locomotives?

Lots of steam locos are powered by oil though
--- old post above --- --- new post below ---

No, in your terminology it is an OMU (oil-fired) (although actually its not multiple-capable therefore is a multi car railcar). Diesel power requires an internal combustion engine ignited by compression. Also diesel fuel is just paraffin really....

Fair enough, it looks a most interesting machine though. I must get to see it some time.

 

[Kentish Paul]

No, in your terminology it is an OMU (oil-fired) (although actually its not multiple-capable therefore is a multi car railcar). Diesel power requires an internal combustion engine ignited by compression. Also diesel fuel is just paraffin really....

Not quite, paraffin is the same as kerosene which is basically the same as jet fuel. Gas turbines though will also run on diesel and pulverised coal dust with suitable modifications.

 

[RAGNARØKR]

Lots of steam locos are powered by oil though

Yes, the Swiss mountain railways just fill up the tanks of their steam engines with diesel and burn it. They were puzzled when they discovered that the steam engines cosumed less fuel than the diesels, when used on the same jobs - they could tell from the amount they were putting in the tanks. This led to an investigation and audit, which showed that in service conditions the diesels were not as efficient as people thought.

 

[NightStar]

A true MU steam locomotive would be the Union Pacific GE built steam turbine electric locomotives 1 and 2 built in 1939.

Robert

 

[jopsuk]

Yes, the Swiss mountain railways just fill up the tanks of their steam engines with diesel and burn it. They were puzzled when they discovered that the steam engines cosumed less fuel than the diesels, when used on the same jobs - they could tell from the amount they were putting in the tanks. This led to an investigation and audit, which showed that in service conditions the diesels were not as efficient as people thought.

Got a reference for that?

 

[Kali]

The odd thing about steam engine nomencalture is that the steam part is the transmission - really they would be coal-steam ( like diesel-electric ) or whatever. That sounds a bit daft though... although it does leave room for things like electric-steam, as the swiss once did.

 

[RAGNARØKR]

Got a reference for that?

DLM-AG.ch

Weird. Not even the manufacturer expected that result.
--- old post above --- --- new post below ---

The odd thing about steam engine nomencalture is that the steam part is the transmission - really they would be coal-steam ( like diesel-electric ) or whatever. That sounds a bit daft though... although it does leave room for things like electric-steam, as the swiss once did.

Depends what you mean by the transmission. There are two stages.

1. Conversion of chemical into mechanical potential energy.
2. Transmission of mechanical energy into power at the rail.

With electric traction, stage 1 takes place at the power station by the burning of fuel.
Stage 2 comprises the heating of water to make it into steam (the working substance), its conversion to electricity in a turbine, transmission down the distribution system, conversion into rotary motion in the trains' motors and transmission of the rotary motion via the gearing system or drive shafts into power at the rail. Efficiency is 2*

With a diesel mechanical system, the conversion of chemical energy to mechanical energy takes place inside the cylinders of the internal combustion energy. The hot combustion gases are the working substance. This cuts out the need for steam boilers, turbines, and distribution grids. All that is needed is to convert reciprocal motion to rotary motion, and the power can be transmitted to the rails by a clutch and gearbox. But the nature of the system means that only limited power can be transferred to the rails in this way and more powerful diesel traction units use the engine to drive an electric generator and the electricity drives the motors. Efficiency is 3*.

In a steam locomotive the combustion of fuel takes place in a combustion chamber just as it does in a power station. The potential energy of the steam is converted to reciprocating motion in the cylinders and there is a direct drive to the wheels. In a locomotive the conversion of the energy in the steam to reciprocating motion is relatively less efficient than in the turbines of a power station or the cylinders of an internal combustion engine, so overall efficiency is only 1*. However, the conversion of reciprocating energy to power at the rail is very efficient as there is no intervening transmission system - just connecting rods and cranks. Combustion systems have also become more efficient in recent years, which has driven up overall thermal efficiency at little. It also happens to be easier to meet increasingly strict emission standards with external combustion as there is better control of the chemical process than with internal combustion, which is explosive.

The initial cost of steam locomotives is also around one-third of that of other traction of the same power, due to their greater simplicity. A steam locomotive consists of a chassis, a combustion chamber, a pressure vessel, a means of converting the potential energy of hot steam into mechanical energy and a system for transmitting this to the wheel-rail interface. The pressure vessel acts as an energy reservoir, allowing a relatively fixed combustion rate but variable power output.

There were obvious technical issues with steam locomotives which led to them largely going out of use in the 1950s but most of the others were resolved in the 1970s. The relatively low thermal efficiency is inherent, but even this has been much improved.

At some point one it would be reasonable to expect this realisation to dawn on those who make decisions about traction policy.

Video

 

[jopsuk]

DLM-AG.ch

Weird. Not even the manufacturer expected that result.

There's a lot of numbers bouncing around on there with little explanation, and bait and switch stuff between mainline light-oil fored steam and yard fireless-shunters.

What I've not found is a direct fuel consumption comparison of comparable power "modern steam" and diesel locomotives.

There's also no external analysis, or references to peer reviewed papers, on the matter. Forgive me if I don't entirely trust claims made about technology on a manufacturers website.
--- old post above --- --- new post below ---

The initial cost of steam locomotives is also around one-third of that of other traction of the same power, due to their greater simplicity. A steam locomotive consists of a chassis, a combustion chamber, a pressure vessel, a means of converting the potential energy of hot steam into mechanical energy and a system for transmitting this to the wheel-rail interface. The pressure vessel acts as an energy reservoir, allowing a relatively fixed combustion rate but variable power output.

Have you looked at the complexity of a late era steam locomotive's mechanical valve systems? Or the intricate detail of the boilers, especially with superheaters?

As for the "relatively fixed combustion" rate, um, no. Just plain wrong.

 

[RAGNARØKR]

There's a lot of numbers bouncing around on there with little explanation, and bait and switch stuff between mainline light-oil fored steam and yard fireless-shunters.

What I've not found is a direct fuel consumption comparison of comparable power "modern steam" and diesel locomotives.

There's also no external analysis, or references to peer reviewed papers, on the matter. Forgive me if I don't entirely trust claims made about technology on a manufacturers website.
--- old post above --- --- new post below ---

Have you looked at the complexity of a late era steam locomotive's mechanical valve systems? Or the intricate detail of the boilers, especially with superheaters?

As for the "relatively fixed combustion" rate, um, no. Just plain wrong.

There is information here. Page 3 deals with operating costs which is the bottom line. The operator appears to have almost laid up the diesels. Nobody else appears to have had the interest in trying to check the claims one way or the other so asking for peer-review in this situation is unrealistic. Scepticism is in order, but even allowing for a manufacturer's rose-tinted spectacles, the result has to be of interest.

The parts count on a steam locomotive is an order of magnitude less than a diesel or diesel electric ie there are a few very big parts instead of many small ones. The fireless ones use on-site steam which is available in some industries.

Combustion rates ARE relatively stable on a steam locomotive. With an IC engine, power output is proportional to engine revs which is directly proportional to combustion rate. Typically, in railway applications this goes from a screaming to idling as the driver pushes the handle over and back again. This cycling was a cause of initial problems with the Valenta engine when this marine diesel, used in constant-speed situations, was fitted to the HST. In the same situation, a boiler acts as an energy reservoir so the combustion rate can be evened-out.

 

[jopsuk]

The chart with the "operating costs" appears to show "new steam" with exactly the same operating costs as "new diesel", which is a rather suspicious result. "New diesel" turn out to have been built in 1975 and 1987.
The second chart is for an Austrian railway, and compares apples (elderly diesel railcars) with oranges (brand new steam).

As for peer review? If the results were as good as they claim, it would be down to them to write up and submit to journals. Short of some sort of conspiracy to suppress such results, I'm sure engineering journals would be very interested in such results. The submitted papers, to be fully accepted for publication, would then be peer reviewed- that is, sent to relevant experts for their review- to check that the science was sound. It isn't about outsiders coming in and doing that research.

 

[Tiny Tim]

Surely Garretts are multiple units?

 

[RAGNARØKR]

The chart with the "operating costs" appears to show "new steam" with exactly the same operating costs as "new diesel", which is a rather suspicious result. "New diesel" turn out to have been built in 1975 and 1987.
The second chart is for an Austrian railway, and compares apples (elderly diesel railcars) with oranges (brand new steam).

As for peer review? If the results were as good as they claim, it would be down to them to write up and submit to journals. Short of some sort of conspiracy to suppress such results, I'm sure engineering journals would be very interested in such results. The submitted papers, to be fully accepted for publication, would then be peer reviewed- that is, sent to relevant experts for their review- to check that the science was sound. It isn't about outsiders coming in and doing that research.

Never underestimate the power of inertia. I think there is just not enough interest in what Waller has been doing. Who would do this research, who would pay for it and what benefit would it be to those who were doing it? And people tend to repeat what they hear, without questioning it. I discovered this in industry when I was told that such-and-such a process had been tried but could not be made to work. When we looked more closely, we found out what the problem had been, solved it with a couple of weeks' research and the company saved a couple of million pounds a year, a lot of money in the 1960s. It was the same with steam in the 1950s. A handful of engineers were committed to developing the technology and worthwhile improvements were made but the perception that it was outmoded meant that there was little interest in the industry as a whole. Pity because the capital costs of steam are so much lower and thermal efficiency was pushed up from around 8% to 12% - not wonderful but bringing overall costs within the range of acceptability.

Waller's UK associate told me that the mountain railway fleets were ordered in the first place to boost tourist traffic when the original steam locomotives were becoming to expensive to run. They were designed to run on diesel as the fuel is easier to handle, it can be burned to give a clean exhaust and they were using it anyway. When the operator discovered they were putting less fuel in the tanks of the steam locomotives it came as a surprise to everyone. Waller then carried out an audit to establish what was going on.

However, a similar thing was found in South Africa in the late 1980s - that modernised steam was cheaper to operate than diesel locomotives, but they replaced them anyway, presumably because of the view that steam was old fashioned. Funny really because steam power is used for most electricity generation.

 

[DXMachina]

Could be as simple as a safety / operational complexity issue. A locomotive with a fully internal combustion engine and many small cylinders instead of one huge boiler probably takes a lot less skill to operate and has reduced possibilities of a catastrophic / dangerous failure.

I often hear of certain iconic kettles being unavailable for extended periods due to the expense of mandatory boiler certificates and the plugging of leaks required to attain them.

 

[RAGNARØKR]

Could be as simple as a safety / operational complexity issue. A locomotive with a fully internal combustion engine and many small cylinders instead of one huge boiler probably takes a lot less skill to operate and has reduced possibilities of a catastrophic / dangerous failure.

I often hear of certain iconic kettles being unavailable for extended periods due to the expense of mandatory boiler certificates and the plugging of leaks required to attain them.

Those iconic kettles are ancient relics long past their use-by date. Inertia is enough to explain it. Modern trains need highly skilled technicians to keep them going.