The reason behind this locomotive - and those "funny" diesel-hydraulics was the interest of the German railways in finding alternative means of propulsion to the steam locomotives of the time. Diesel-fired locomotives and electrification were seen as the way of the future, which they inevitably became. One of the first major achievements in diesel locomotive engineering was a 1000 PS engine of the Royal Prussian State Railways that was placed in service in 1912.
Now the locomotive itself wasn't a bad concept, but its transmission was. Its means of propulsion transfer was purely mechanical (imagine double clutching the thing), which presented numerous maintenance and operational problems, enough that a new solution was soon sought after. This resulted in
V 3201, the aforementioned diesel-pneumatic locomotive. It was effectively a large diesel engine - the exact type that was later used in U-boats no less - connected to a single stage compressor that powered the air drive system - at a pressure of 7 bar - which was really no different than that of a steam locomotive. It didn't work very well. The heat generated by the compressed air made the compressor quite prone to overheating. It wasn't in service for very long, mostly because it just didn't work. Five years after it was delivered to the DRG in 1927, it was taken out of service.
The trouble with diesel locomotives at the time was that there existed no particularly efficient means to transfer the engine's power - not especially in the case of something with several hundred or even a thousand horsepower - to the drive axles that was reasonably reliable. This was much easier to do with electrics and steam locomotives for very obvious reasons, alas the diesel locomotive remained an engineering curiousity and a bit of a problem for the German railways until 1935 when an experimental locomotive with a hydraulic transmission -
V 140 001 - was built, meant as a prototype for a whole new series of modern, diesel-hydraulic locomotives for branchline service. This locomotive was built with the following performance requirements in mind:
- The ability to pull a 500 ton train up a grade of 1 in 100 at 30km/h
- A top speed of 100km/h
- The ability to work as a grade engine remotely controlled by the lead engine
It soon proved itself to be just as good as its steam-powered compatriots, and immensly reliable, far more so than any of its experimental predecessors. Unfortunately the planned series production never saw the light of day. A war came along and the industrial strength that would've been required to make these locomotives instead went to making weaponry for the German military. V 140 001 was taken out of service in 1939, not because of a serious breakdown or anything, but because of fuel shortages that prevented it from being used regularly.
After the war it was used in the Frankfurt am Main area until it was taken out of service in 1954; again not due to any serious problems with the locomotive itself, but because with it being a lone prototype there weren't any spare parts lying around to keep it running. By this time the DB had taken delivery of its ten
V 80s (a new generation of diesel-hydraulics upon whose technology most subsequent diesel locomotives in West Germany were based) which were in service in and around Frankfurt as well, so a replacement already existed.
The German Federal Railways of West Germany stuck with diesel-hydraulics for its unelectrified lines from that point onward, resulting in the
V 60s and
V 90s as shunters,
V 100s and
V 160s as branchline and mainline locomotives leaving
V 200s primarily for mainline service. In East Germany diesel-hydraulics weren't as widespread as they were on the other side of the border. A large number of mainline locomotives were diesel-electrics that had been imported from the Soviet Union. Still, they managed to build their own after a while.
V 60s were relegated to shunting duties like their West German cousins, with
V 100s and
V 180s taking over the rest. One thing I must note is that East German V 100s and V 180s use hydrodynamic transmissions, but for the purpose of keeping this fairly simple, let me just say that they're close enough.
Steam locomotives nevertheless remained the daily staple of locomotion in both Germanys for a long time despite their younger, more modern brethren running on the same rails as they did. West Germany's Federal Railways dropped the fire for the last time in 1977, while East Germany more or less held on to steam till shortly after the two Germanys became one in 1990.
All of these classes are still in service to some degree, despite the fact that some of them are now almost (if not already) half a century old. This is a testament to their reliability and robust build quality that has managed to soldier on into the 21st century with DB AG and numerous private companies. V 90s present the largest number of engines that are still in service out of the number originally built, with all but a few of the 408 built still running around. Since the 1970s there have been few new diesel-hydraulics built, mostly because the sheer number of those already existing didn't really require it. There are some though which are being bought by private companies, and as of 2010 the DB will start taking deliver of some new shunters from Voith to gradually replace its V 90s. One noteworthy modern diesel-hydraulic of German production is Voith's
Maxima 40 CC. With 3600 kW it is the most powerful diesel locomotive in Europe. It can put out up to 519 kN of tractive effort and can continually put out 408 kN. With a top speed of 160km/h (or 120km/h, depending on the customer's wishes) it can also keep up with modern German electrics and is in fact faster than all of the diesel-hydraulics that were built in East and West Germany in the postwar years. It is for the moment the epitome of diesel-hydraulic locomotion, only time will tell if it lives up to the expectations of its builder and its purchasers (77 are on order as of writing).
My three cents (inflation adjusted).
WileeCoyote
