How a railway disel engine works?

Question

Railway that runs on disel engine, how it works? About disel engine and the electricity it provides in rail coach, how it is done?

Answer 1

Virtually all diesel locomotives use diesel-electric.  The diesel turns a large generator, which makes electricity... then the electricity drives large traction motors hung on the axles.  That's how propulsion is done.  Yes, trains are electric vehicles!

Now, power for the passenger coaches comes from an auxiliary generator on the locomotive.  That auxiliary generator is either attached to the main locomotive engine, or to a second diesel engine whose only purpose is to drive the generator.

Driving it off the main diesel engine is tricky, because the coaches depend on fixed voltage and AC frequency.  So either the engine must run at a constant speed for constant frequency, or there must be sophisticated electronics to convert the power to the correct voltage and frequency.

If the locomotive is electric (overhead wire or third rail) then sophisticated switchgear controls the amount of electricity supplied to the electric motors.  A motor-generator set, or more likely a sophisticated inverter, supplies AC power to the coaches.

Answer 2

You might mean a specific railway I am not aware of but generally speaking, all locomotives are electric locos with a deiesel engine running a generator or alternator to provied the electricty. This is also done on most passenger trains also, even the self propelled "Bud Cars". As for the coach power some passenger deisels have an auxilary generator for that purpose but a lot of coaches, particularly the private owned luxury ones have a built in generator, much like luxury motor homes.

Answer 3

Diesel-electric locomotives are the most common..  The diesel engine turns a generator, which provides electrical power to the traction motors that turns the wheels.

Passenger diesel-electric locomotives like Amtrak's F40PH and AMD103s also have an HEP (Head End Power) generator which provides electrical power to the coaches the locomotive is hauling.  (The diesel engine aboard the locomotive also turns the HEP generator).

Hope this helps.

Answer 4

Locomotives using the Diesel engine as a prime mover have seen 2 different ways of propulsion:

1.  The Diesel engine output shaft is connected to either an A.C. or a D.C. generator to provide electrical power which eventually goes to the traction motors.

2.  The Diesel output shaft is connected to a hydraulic drive system which gave much greater horse power per unit weight than diesel electrics.

In the 1950's, German locomotive manufacturer Krauss-Maffei showed that with hydraulics transmission adhesion was much improved over electrical methods.

In 1961 two U.S. railroads each purchased 3 of these locomotives, the Denver & Rio Grande and the Southern Pacific.

Regarding passenger car power:  In the early days of the railroad, passenger cars in the train were heated with steam from the locomotive and generated their own electricity from a wheel driven generator on each car.

Head end power (HEP) is the electrical equivalent of the locomotive-to-caboose air line. This electric line provides the "hotel load" power to every car in the train which is a substantial electric load. For each individual car in the train, this power (generated by the locomotive or a generator car) provides electricity for the lights, air condition, heating, receptacles, etc. For the railroad, the major benefit of HEP is that cars do not need to generate their own power (simplifying equipment) and cars have power even when they are not moving. Amtrak also has standards to pass communication cables along the length of the train from car to car.

Amtrak has changed their regulations so that for any car to be certified for use with Amtrak, regardless of its position in the train, it must be equipped with HEP in order to pass electricty along to the rest of the cars in the train. This entails the transfer 1.2 megawatts of power (four cables, each carrying 400 amps at 480 volts, 3-phase).

If the generator is being powered by the locomotive's prime mover, the engine must rotate the HEP generator at a constant speed (rpm) to maintain the required 60 Hz AC frequency output. Therefore, a typical General Motors EMD locomotive, in HEP mode, will operate at its full engine speed of 900 rpm, driving the generator at 1800 rpm through a 1:2 gearbox. As a noise reduction method, the locomotive's main (traction) generator can also supply HEP, usually at 720 rpm. However this operating mode is only available when stopped.

The advent of power electronics has allowed the engine to operate over a larger speed range and still supply a constant HEP voltage and frequency by means of inverters.

All power consumed by HEP is at the expense of traction power. The 3200 horsepower (2.4 MW) P32 and the 4000 horsepower (3.0 MW) Genesis-Series P40 reduce to 2900 (2.2 MW) and 3650 horsepower (2.72 MW), respectively, when in HEP mode.

HEP power supplies the lighting, HVAC, dining car kitchen and battery charging loads. Individual car electrical loading ranges from 20 kW for a typical car to more than 150 kW for a Dome car with kitchen and dining area, such as Princess Tours Ultra-Dome cars operating in Alaska.

Because of the lengths of trains and the high power requirements, HEP is supplied as three-phase AC at 480 V (standard in the US and for Canada's VIA), 575 V (GO Transit, Toronto), or (rarely) 600 V. Transformers are fitted in each car for reduction to lower voltages.