Krauss-Maffei Diesel-Hydraulic Locomotives

[Anonymous]

Still making an effort to continue my research on these unique locomotives from Germany that were used during the decade of the '60s by SP and D&RGW.  Also, would like to know if there are any videotapes that have the sights and sounds of these engines in operation.  Your help in this matter will be greatly appreciated and will be properly listed in any future printed information.  Also, please feel free to contact me at my e-mail address: [e-mail]

[Philcal]

I seem to recall Trains doing a feature article on the KMs back in the 70s. I know I read a very good article on the locomotives about that time. The Trains archives might be of some help to you in checking that out. From all accounts, the KMs were really powerful engines, with one unit having the horsepower and pulling ability of two or three EMD or ALCO units. What proved the undoing of the KMs was the area(s) they operated in, and the American practice of running a unit 24 hours a day or more. The KM technicians who accompanied the units on their American debut were astounded at operating practices on the SP and D&RGW. The SP used at least one KM as a camera car training unit for new engineers. To the best of my knowlege, none were preserved.

[PBenham]

That SP camera car is awaiting restoration at the California State Museum in Sacremento! The restoration would have to be cosmetic, however, since the engine and transmission are long gone.

[CSSHEGEWISCH]

The KM's also suffered from being oddballs in a variety of ways.  The Maybach engines were decidedly non-standard, being smaller and quicker running (higher RPM) than North American railroad diesels.  They also had an all-pneumatic throttle system which was difficult to maintain and made MU capabilities with other models impossible until they were rebuilt with electric throttles.

In the end, the horsepower race caught up with the KM's.  When they were purchased in 1961, the main offerings were the GP20/SD24, U25B/U25C and the RS27/RS32/RSD15 lines.  By 1967, the SD45 was on the market and KM's became the hard way of getting the same HP as an SD45.

It would also be interesting to find out how well they worked out on the meter-gauge E.F. Vitoria a Minas (of DDM45 fame) in Brazil. 

[PBenham]

The KM's also suffered from being oddballs in a variety of ways.  The Maybach engines were decidedly non-standard, being smaller and quicker running (higher RPM) than North American railroad diesels.  They also had an all-pneumatic throttle system which was difficult to maintain and made MU capabilities with other models impossible until they were rebuilt with electric throttles.

In the end, the horsepower race caught up with the KM's.  When they were purchased in 1961, the main offerings were the GP20/SD24, U25B/U25C and the RS27/RS32/RSD15 lines.  By 1967, the SD45 was on the market and KM's became the hard way of getting the same HP as an SD45.

It would also be interesting to find out how well they worked out on the meter-gauge E.F. Vitoria a Minas (of DDM45 fame) in Brazil. 

Considering that EFVM bought GEs (new and rebuilt) speaks volumes. Their roster is mostly rebuilt Dash8 40Bs, converted by GE do Brasil to Dash8 40 B-Bs. In addition to rebuilt C36-7s,C-30-7s and B39-8s, They also have new meter gauge Dash 9 44CWs, built in Brazil.

[chad thomas]

SP Trainline had a KM article not too long ago. I think it was the fall issue last year. It's worth checking out.

[Philcal]

At the time of the KM purchases by the SP and D&RGW, both roads were looking for some serious horsepower. The KM units seemed to fill the bill, and were able to pull trains single handedly, that would have required two, three, or more EMD's or Alco's. The KM's arrived on both properties with high hopes and considerable expectation. They were set up and put to work immediately, and that's where the problems began. The units began to experience problems with the Diesel-hydraulic transmission the units were equipped with. The factory technicians who accompanied the units could not get over the American practice of running a unit 24 hours a day, with stops only for crew change, inspection, water and fuel. The first KM units to arrive in the US had a distinctive European appearence. Later units looked a little more "Americanized". I believe the units ran into the mid 60s,before being retired. One SP unit was retained as a "camera car" for engineer training. In this role, it was pushed by another unit.

[DSchmitt]

The KM's were not the only diesel hydraulics on the SP.  Alco delivered 3 units (DH-643) numbered 9010-9020 in September 1964.  They each had two Alco four-cycle 251-C V-12 diesel engines developing a total of 4300hp and imported hydraulic transmissions by Voith.

They were renumbered 9150-9152 in October 1965. 

When the KM's were retired in 1968, the Alco's remained in service.  They were renumbered again 9800-9802 (probably in 1970 to make room for new SD45's)  and scraped in 1973.