CSX Freight Train

[Piwoslaw]

Another discussion lead to trains and that got me thinking (yes, it happens):
When does a train need the most power? Either going up a hill or starting from a station/junction.
When does it have a surplus of energy? Either going down a hill or braking before a station/junction.

So, the electric assist would not only be on hills, but also within 2-3 miles of a station/junction. On a hill, electric helper engines would be added to the train, but in the case of simple acceleration/deceleration the loco itself would have to be able to channel the energy into the catenary. How much would have to be changed in the construction of a typical diesel-electric loco to allow it power its wheels straight from the overhead grid? Since the catenary cables wouldn't be longer than 2-3 miles in each direction, then there is no need for outrageously high voltage, the voltage can be what ever is used in the electrical side of the engine, so no need for the large, heavy transformers that make up most of a pure electric loco.

And what about storing energy on-site? Instead of timing trains to go up and down hills, or start and stop at a station, at the same time, the hill/station/juction could have a device for storing energy. Since it wouldn't be mobile it could be large and heavy, and since it would be in an area with frequent train passes it would only need to store energy for no more than a few hours, usually for less than an hour. I'm thinking water pumping, flywheels, ultracapacitors, whatever. This would also allow the device to be gradually charged from the grid and then give that energy back in a burst.

[Bicycle Bob]

Locomotives need weight for traction. New rolling stock could be designed with motors and electrical hook-ups at the couplers, but schemes such as rack-and-pinion arrangements to enhance traction have never been trouble-free. Self-powered cars with smart couplers can be much lighter and more versatile. I'm amazed to see diesel-electric drives being installed in new ships, after the 1st two ferries ballasted that way died of old age without being emulated.

FWIW, during a long power outage, Montreal City used a locomotive generator to power up some buildings to provide essential services. Hydro Quebec had said it couldn't be done, but they were busy.

[Big Dave]

Locomotives can generate power for buildings.

1. Open building disconnect
2. Line up locomotives
3. Disconnect the rectifier (converts AC to DC)
4. Forget step 3 if the locomotive is new enough to use AC traction
motors
5. For older AC/DC locomotives, set to throttle 5. It gives you about 1.5 MW @ 460 volts, 55 Hz.
6. For newer locomotives, set the VFD at 60 Hz and run her WOT. You should get about 3 MW/unit @ 460 volts

Old hat to railroaders.

[jamesqf]

Originally Posted by Bicycle Bob

...but schemes such as rack-and-pinion arrangements to enhance traction have never been trouble-free.

The Swiss seem to manage them quite well. There are a lot of little spur railroads going from the valleys up to mountain villages, using the rack-and-pinion arrangement to climb what looked to me like about 1 in 3 grades.

[Bicycle Bob]

It is good to hear that rack and pinions have been made to work where needed. Any news on reliability in winter? Is the rack covered? Sealed?

[jamesqf]

Originally Posted by Bicycle Bob

It is good to hear that rack and pinions have been made to work where needed. Any news on reliability in winter? Is the rack covered? Sealed?

The racks (of the ones I've been on, anyway) aren't sealed or anything. I don't know much about reliability, but most have been operating year-round since the late 19th/early 20th century.

[Big Dave]

Rack & pinion railroads work OK for short distances where there is no other way to beat the grade, but nobody ever accused them of being overly efficient.