Diesel-hydraulic power transmission in locos/RDCs

[ebediant]

In the late 60's Alco sold some diesel-hydraulic locos; they did not prove themselves well. About this time, Krauss-Maffei of Munich, Germany sold some six-axle 3000HP diesel-hydraulics to Southern Pacific and the D&RGW. These also proved troublesome. The most successful application of hydraulic transmissions to rail eqpt. was with Budd's RDCs in the mid-50s; some of these were still running on branchlines when Amtrak took over in '71; a few survive in Canada and Mexico.

[CSSHEGEWISCH]

Diesel-hydraulic (torque-converter) transmission barely worked in the United States mostly because it was non-standard with all of its associated problems such as lack of parts, experienced mechanics, etc. The KM's were really up against it with their Maybach engines which were oddballs in a world mostly populated by 567's, 251's and FDL's. Also, the horsepower race caught up with the KM's and an SD45 was an easier way to get 3600 HP then a twin-engine KM.
RDC's worked best with railroads that had substantial fleets such as B&M, CN, CP & NYC. It would be interesting to find out the availability factor of RDC's on the various roads that only owned a handful of them.
By the late 1960's, surviving RDC's were overwhelmingly in suburban service (B&M, NYC/PC, PRSL, RDG) with only CN and CP remaining as substantial branchline operators.
VIA still had a substantial number of RDC's into the 1980's, but most of them were concentrated in short-haul service in Eastern Canada.

[SSW9389]

Alco's 3 DH643s were built in 1964 along with 15 Krauss Maffei hood units imported that year. The 6 Krauss Maffei cab units were imported in 1961. All 24 of these diesel hydraulic units were working on the Southern Pacific in 1964. By 1968 all the Krauss Maffei hydraulic units were out of service. The Alcos hung on until 1973.

[Anonymous]

Alaska Railroad still uses 4 of its RDC's (there are 5, but #5 is a hanger queen)