There is no debate about if they failed in the United States. They did. With a different maintenance philosophy, they succeeded in Europe, primarily Germany and the UK. There are still examples of them in regular service 50 or more years after they were built.

We are not in the business of trying to justify the existence of the diesel hydraulic concept nor what they are called. Those decisions are up to the reader. If one believes that they were not properly called "diesel hydraulic", that is fine. Whatever rings your bell. Just because they were called that in Europe, on the Rio Grande and on the Southern Pacific doesn't mean that you cannot call them whatever you want.

We are only in the business of trying to preserve the only remaining example of a grand experiment on the Southern Pacific railroad. Judging by the donations received to purchase and transport the trucks (there, I said it), a lot of people like the idea.

Howard

No need to get defensive. I think your project to preserve this unit is incredible and I commend you for it. Preservation is not only about the unequivocal successes. There are so many less than successful things that should have been preserved but were not. The various steam turbines and the divided drive engines come to mind. And the KM's were not failures in the flat out sense that term brings to mind; just not up to US railroads' desires in terms of performance AND minimal maintenance labor. To have one not only preserved but perhaps running is awesome.

Yes, mek-hydro is my personal preference to set apart from a hypothetical machine employing only pumps, tubing, and motors and also to note that if one removed the torque converter and replaced it with some purely mechanical gizmo, 80% of the drive train would remain the same. I just figure that in the interest of descriptive accuracy, the system that encompasses so much of the drive train be included in the name. That is the rationale. I respect that most everyone else just says hydraulic and is unlikely to change.

My comments are directed at furthering discussion. I wonder if this technology will be revisited someday or whether electric transmissions, which already beat hydro at the 60's level of technology, have pulled even farther away. If the price premium on AC traction continues to decline, given the performance advantages coupled with what I presume is a huge decline in traction motor maintenance costs, the latter seems more likely.

Steve

I think its a great idea to make it operable....
As to why they failed here in the US? probably due to the fact that they were "different".... Maintanence people probably hated them, So they didn't keep up with the needed work.

Great news! I have been following this restoration for years, and now with the possibility of actual operation, I need to start thinking about a trip west! What is the plan for the missing shafts? Is there something that can be modified to work or will you have to build from scratch?
Excellent work by the restoration crew, my hat's off to you!

Our railtrack equiptment was all electric powered with the voith gearbox that name is what caught my attention. We had a driveshaft break and rewelded the ends on 6 inch tubing then had it balanced. Now there is a diesel hydraulic powered push out tractor (Goldhoffer) from Germany it is fast and can pickup up the landing gear on airplanes and push or tow. The German's seem to like hydraulic powered equipment. I think the Krause Maffei when imported were the most powerful locomotives in the USA and made EMD up the power output of their own. hocarsandtrains James French

The company who originally provided the cardan shafts to Krauss Maffei is still in business and can make them for us. In fact, we have a quote from them for the construction. This will be our next fund raising effort. Unfortunately, due to the torque that must be transmitted during engine cranking (the starter motor is on the transmission), their length and the high engine horsepower, the requirements for the shafts are quite stringent so we have decided against trying to modify any existing industrial shafts.

When you decide to make the trip, contact me through the SP9010 web site. :-) And thanks much for your kind comments.

Howard

Is there a diagram somewhere that shows the arrangement of the gearboxes and shafts? Didn't see anything on the restoration web site that would help me understand the power transmission arrangement.

Will be watching for future donation opportunities!

The primary reason they failed was due to the engines, not the drive system. The Maybachs were very expensive to maintain and did not stand up well to the rigors of American railroading. For example, one can remove the cylinder head from an EMD in a few hours. It is a relatively simple job and I personally have done it quite a few times. The problem with the Maybach is that it is a overhead cam engine which means that one has to remove the entire cam box in order to remove one head. The fuel injection, return, and leak-off lines are one assembly, so it must be removed from that bank. Not to mention that part of the engine hood and 4 doors have to be removed in order to get the cam box out. I have never read how long it would take to remove a head but, it is much, much longer than any EMD, Alco or GE. Plus with a pre-combustion chamber and six valves, the heads were complex and expensive to replace.

And, consider that in order to replace an assembly (head, cylinder liner, piston and connecting rod), the engine had to come out of the locomotive. The list goes on.

Don't get me wrong, the Maybach is a beautifully made machine but it requires a level of attention that just did not fit into American railroading.

Howard

This should help. I will see about adding some technical information to the web site.

And your donation will be welcomed.

Howard

Hey Howard, would you have any comments about the so-called Alco-haulics? Those would have combined a reasonably reliable and familiar prime mover with a similar transmission though still fighting an uphill battle against being the oddball. I've never read anything about their performance other than them not lasting too long.

Steve

Wish I did. I find them fascinating from an engineering point of view. They used the Alco 12 cylinder 251 engine and Voith transmission and records do not seem to indicate any particular failure history. It seems that their largest problem was their uniqueness. The did last a little longer than the KM's but as they failed, they were not repaired as the experiment had run its course. The last one gave up a truck and transmission to preservation at the California State Railway Museum.

Howard

A diesel hydraulic Shay........interesting.

dave