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[M636C]

ndbprr,

What you were describing at the start of this thread is not very different from a Shay type locomotive. Combining this idea with the modern drives in diesel hydraulic locomotives, there is no good mechanical reason not to build a steam locomotive with that type of drive. The economical argument still applies, however. But if oil shortages became serious and coal was available, a steam locomotive could be built much more easily than a coal burning gas turbine, for example!

Peter

[CSSHEGEWISCH]

The coal-fired gas turbine experiment by UP in the 1960's was a rousing failure. Unless they come up with a way to eliminate the fly ash, this design is a dead end.

I read somewhere that the adhesion advantage of the diesel-hydraulics was due to the coupled axles, and this could be applied to diesel-electrics (GE 45-tonner).

[foamer4000]

ndbprr
The Diesel hydralic was a failure. The Grande sold theirs to the SP after a transmission exploded and destroyed a cab. Thankfully the cab was unoccupied. The coal fired gas turbine was a failure becouse coal is a little abrasive for a jet engine. And in todays society fly ash is not acceptable. I can compare the 3985 to what can be done today, just as I could compare a 1942 car to a modern automobile. With the manufacturing abilaties of 1942, compared to the abilaties of today, the 1942 product was superior. It was a quality product. The 1942 product was as state of the art as possible. The problem with the 1942 product vs the 2004 product was that failure was acceptable in 1942. Today failure and down time are not acceptable. The Union Pacific expects over 90% availabilaty from its power. Any steam locomotive ever made could not come close to this number. The problem with a steam locomotive is that it is steam powered. Steam and metals do not wotk well together. High temperatures and metals do not work well together. A steam locomotive in any form 8000 feet from the opperator is not feasable. And lets not forget the lawers. When one of these boilers fails and kills an employee, that is another set of problems. Lets not forget the reasons steam was abandoned as fast as possible. Polution, excessive noise, excessive labor costs, unreliabilaty. As far as the fesability of a turbine. A turbine is not a good generator of electricity in rail applications. A turbine is unresponsive and consumes a large quanity of fuel or steam. I beleive that your idea of a gear driven transmission for modern heavy haul railroading is infeasable becouse of the excessive size of the components needed.
Does anyone have an idea of how many man hours it takes to service and inspect a boiler? It is quite extensive. That amount of time costs money. That is another reason that steam has died. Railroads culd not afford them. Remember railroading is a for proffit business. Railroads will do what is economically fesable, they are not in business to develop pipe dreams of foamers.
Foam-on

[M636C]

Foamer4000,

Perhaps I haven't quite made the point I was trying to explain. The hydraulic transmission would not be required with a conventional steam engine. A diesel needs to run at speed to develop power, but a steam engine can develop power from stand. What I was suggesting was to use a compact multi cylinder engine like that in a Shay locomotive (but built to modern standards) using the modern drive shafts and axle drives developed for diesel hydraulics to take the power to the rail. Those items, like truck driveshafts and differentials, are well developed and quite reliable. They would also remove the strict speed limits on the old shay design. This would give a locomotive with 100% adhesion and no rotating or reciprocating balance problems.

Peter

[foamer4000]

Peter
What a complicated idea. First no locomotive can acheive 100% adheasion. ( with the exception of cog rail units) The problem with your proposal is that it combines the most undesireable properties of steam and diesel hydralic. A mechanical drive line is a matinence issue, no matter how well constructed, it will still fail under American heavy haul railroading. The mechanical connections can not take the abuse of a 16 thousand ton train running in and out on the drive train. The other disadvantage of having all of the rail drive wheels ridgedly connected is accelerated wheel and rail wear. How are you going to devise a drive system that can accelerate from a dead stop to over 70 mph without changing gears?
If you ever have a chance to study steam locomotive power curves, you will notice that a steam locomotive can pull more at speed than it can start. The steam locomotive power curve starts out at a modest level and rises as the speed of the drive components increase to the limit that steam can be exchanged in the cylinders. A high load on a stationary steam locomotive will cause it to stall. The boiler on a steam locomotive has all of its energy stored when it is at full opperating pressure, the problem is to transmit this energy efficiently. The diesel engine has the same torque output prettymuch at all engine speeds. The diesel locomotive changes opperating rpm to change available voltage to the electric transmission. The diesel electric can pull with all of its abilaty from a stand still. It also can go from a standstill to maximum speed without engaging any type of gear train. ie :mechanical transmission. (yes their is a pinion and bull gear in the traction motor assembly) Have you thought about what type of electronics that will be needed to monitor and opperate your proposed locomotive. Remember it must be able to opperate at speeds of less than 1mph continuosly, and be able to run at over 70 mph with no adjustment. It must be able to be controled remotely also, by mu and as a dpu.
You have an interesting concept. The speed limit of a shay was the product of small wheels and gear reduction. 15 mph was all it could do.
Foam-on

[M636C]

foamer 4000,

Again, what I meant by 100% adhesion was that the whole locomotive weight was available for adhesion (no idler axles), not that you could rely on more than 25% adhesion at the wheels.

Are you familiar with Oliver Bullied's "Leader", built at Brighton in 1948? This included so many hare-brained ideas it could never have worked, but if it was simplified, it could have filled a useful niche. I don't think steam could do all the things we now do with diesels, but we don't have to go back to the century before last just to get something that works.

Electronic control systems are fairly flexible these days. I wouldn't see that as a problem unless the specification was too ambitious (as is often the case with software today).

Peter

[foamer4000]

Peter
Look at page #90 of the March 2004 trains. It has a nice picture and a short message on the Espee Krause-Mafia units. The modern AC units achive over 40% adhesion. I belive the next advancement in propulsion will be the replacement of the diesel powerplant with something more efficient. The current generation of diesel electric units have replaced the last generation on a 2 for one basis. I used to watch coal trains grind up Tennessee pass. It would take the Grande 5 leaders, 8 midtrain, and 4rear SD40T-2's to defeat the 3% grade. After AC power was established the same train ran 2 x 2 x 2. That is a savings of 11 units!
I do enjoy steam myself but the realities of its shortcomings make it an unsutable propultion system. The onlyway that I think it could make a comeback in railroading would be to use a closed tube boiler and steam turbine like a power plant. The problem would be that turbines do not respond well to load changes.
Foam-on

[Anonymous]

i thinks that electric trains are more cheap BUT we need to perseve all the steam engines like The Flying Scotsman, The Mallard and The City of Truro all of these need to be kept in good condition to run on toursist atrctions