Peter Bowen wrote: > o It is easier to control the torque, and it's all there at startup > when it is needed the most. Steam is the same way - which is why it > lasted so long.
Yeah this is pretty much *the* reason for diesel electrics. A gear transmission that can handle 3000-4000 hp would likely be very difficult to build, if it's even possible. Also syncing 3 or 4 engines would be hard with a transmission (see below). > Direct drive mainline locomotives would be an engineering and > maintenance nightmare... There are a number of switching locomotives > that are direct drive though. Actually in Europe lots of small trains between villages are direct-drive diesel[1] where there're no electrical lines overhead. It's a bit interesting as sometimes it takes a moment for all two or three cars to shift gears. If I recall it seemed like there were 3 or 4 gears the train went through between zero and 80 or 90 kph. Each car was self-contained with an engine and transmission. It seems like they are being replaced with diesel electrics in many places, though. Very nice units too, I might add[2]. Michael [1] http://en.wikipedia.org/wiki/Diesel_multiple_unit#Diesel-mechanical [2] http://en.wikipedia.org/wiki/Talent_(train) /* PLUG: http://plug.org, #utah on irc.freenode.net Unsubscribe: http://plug.org/mailman/options/plug Don't fear the penguin. */
