Krauss Maffei: America's Diesel Hydraulic Locomotives

Yes, yes, I know I got the thing about traction motors wrong...

In the 1960s, the Southern Pacific Railroad was shopping for the most powerful locomotives it could find, with no domestic offerings suiting their wants. One company over in Germany offered a solution with some unconventional means, which lead to some interesting results.

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[deadfreightwest]

I seem to recall reading that during initial runs, they had KM people on board to assess performance. One was in the cab and they were at full power on a mild gradient. After a period of time, he nervously asked, "how long is this mountain grade?"
The reply was, "Mountain?! That's another hour away at least."
"Mein gott..."

[shootmyhead]

In Japan, where domestic diesel-electric locomotives didn't do well, diesel-hydraulics flourishes. Today, the JNR DD51 and DE10s are still in service.

[rolandsieker]

“Diesel-hydraulic is still prevalent in Germany” *shows picture of German railways with more than a dozen *electrified* tracks and some half dozen *electric* trains.* Hmmm.

[mikeblatzheim]

"Neigbouring Finland" well, not really, as you'd have to go through Denmark and Sweden.

In Germany the class 200 Diesel hydraulics lasted into the 80s, and the class 218 from the 60s is still in limited service today. The issues with the hydraulic drive have more or less been solved, allowing the locomotives to perform in a variety of tasks that would otherwise require a six axle locomotive. Tasks include pulling long distance Intercitys and regional trains, as well as shunting and heavy freight, and pulling broken down ICEs.
Over here Hydraulics are still being built, mainly with the intention of running heavy trains over lines with limited axle loads without the need for a heavier six-axle locomotive, or for tasks which feature lots of shunting or inclines (basically everything you need a lot of tractive effort for). In Europe in general train companies have moved away from six axle designs, as those apparently cause a lot more wear on the rails. This means that even our 7, 000+ horsepower electric freight locomotives have only four axles, and that the advantages of a hydraulic transmission justify the increased maintenance costs.

[Greatdome]

There were three torque converters in the transmission, each connected to a different gear ratio. To change ratios as the locomotive accelerated, oil from the low gear torque converter was drained into the intermediate torque converter, and again to the high speed torque converter.

[BOBXFILESa]

In the 60s, I had a Rivarossi A-A D&RG Krauss-Maffei locomotive set. Ran very well, but there were no Mountains on my 4X8 plywood!

[ryandavis]

The traction motors did not wear out because of the multiple units but because of the heavy trains they were pulling. Also the locomotives were expected to come up to road speed quickly which is what horsepower is all about. This creates high amperage situations that cause the electric traction motors overheat. This is the reason for the amp gauges in the cabs and the short time rating tables found with them.

The real problem in the early sixties was transition control. The higher horsepower means that at some point the voltage is higher than the amps creating an opportunity for flashover. Think path of least resistance. This is dangerous thus is controlled by traction motor field shunting and switching from series parallel to full parallel.

The higher the horsepower the more complex the transition system becomes and the certainty of failure. Add in the training of the electrician and time for diagnostics what you get is a unit that is out of service longer.

What changed?

The AR or alternator rectified to DC keeps the need for complex transition control to a minimum.

Before anyone starts to negate this they should stop and think.

This is what I do for a living.

They may school me only if they can identify these labels and identify their functions.

FTR, BTR, S, P, IR, FSC, BF, SF, Barco, BSLC, TSM, ORS, TRCS?

[Finntrans]

7:55, in Finland, the Dv12 is still in active use and they were produced between 1963-1984, being the most popular diesel-hydraulic locomotive in the country. Not as powerful as in the US, but very reliable, even the oldest ones.

[ThomasEide]

Remember the SP enjoyed overloading engines! Higher HP to SP meant increase the tonnage. The SD24s failed only cause SP had the mentality of what I stated above. Also the company compared everything to the SD9 for tonnage. The SD24 had more power to increase speeds with the same tonnage is what EMD marketed. Yes even the SD45s were over maxed on tonnage. Not surprised on the KMs since SP had that mentality as stated above.

[russellbrown]

The technical solution to the traction motor problem was the AC drive, but this had to wait on the development of high power solid state inverters.

[markfrench]

The last unit on the Espee suffered from a broken drive shaft not a broken axle. The 4000s had a problem with the U joint on these drive shafts breaking that you didn't mention.

[ericzerkle]

I worked for a company that used Krauss Maffei plastics extrusion equipment. Very high quality and built like a tank!!

[kellingc]

I had no idea these existed. That you for posting. As a fan of the SP, you'd think I knew something about them, but now I do.

[davidgriffin]

Actually EMD built their first 4000+ hp locomotive in 1970. The SD45X. It had 4200 hp from a 20 cylinder 645 engine. 6 went to the Espee (SP) and 1 was retained by EMD as a text vehicle. Montreal Locomotive works built one also. the M640. It has 4000 hp from a 18 cylinder 251 Alco designed engine. It was built in 1971.

[onkelfabs]

About Grrmany:
There were a lot of issues with the early post war diesel hydraulic engines. They weren't fixed up until the mid 60s. Then diesel hydraulic transmission indeed became a very reliable technology.

And Germany isn't neighboring Finland.

[thetrainshop]

A bit of a correction. The Alco C855, EMDs DD35s and 40s, and GEs U50s technically did beat the ML4000C'C's dual engine combined horsepower output. As for Single Engine output exceeding 3999HP, credit I believe goes to the Kestrel in the UK, and between the M640 and SD45X in North America.

[ZLDSmogless]

Diesel-Hydraulic in the UK powers Diesel Multiple Units (DMUs), and the locomotives are Diesel electric.

[paullangford]

The advantage of the hydraulic transmission was that all driving wheels were locked in sync, so they could get much higher tractive effort than the electrically-driven axles. But the limitations of an engine that wasn't designed to run all day at full throttle was the big issue.

[sarahbethsmile]

There is one that still exists 9010 still runs tourist operations but the engine it self did not work so a engine behind it had to push it but now 9010 is in the shops were the workers are planning to get its engine running again for the first time

[RANDOMNATION]

My Grandpa retired from GE in the early 80s. He operated a machine that wound copper wire on motors for diesel electrics.