Hydrogen powered train

[Hyperion]

BNSF built a hydrogen fuel cell locomotive nearly a decade ago.  Though i cant get into too many details on why it's not been seen much since it was trotted out for the politicians to see, the technology has some issues.  It'll remain in the realm of lower gross tonnage for the distant foreseeable future.

[MK]

Somebody call Elon Musk! 

[nkalanaga]

The main problem with fuel cells is scaling them up to the power levels needed for a locomotive.  For relatively small loads they're great.  For large loads a combustion engine of some type is usually easier to build.

For a hydrogen locomotive I'd be tempted to try a gas turbine, with AC motors.  Train speed control would be by frequency, rather than voltage, so the limited speed range of the turbine wouldn't matter much.  It, and the generator/alternator, could put out a constant voltage, and the inverters would handle the speed control.

[peteski]

For a hydrogen locomotive I'd be tempted to try a gas turbine, with AC motors.  Train speed control would be by frequency, rather than voltage, so the limited speed range of the turbine wouldn't matter much.  It, and the generator/alternator, could put out a constant voltage, and the inverters would handle the speed control.

Isn't that the de-facto standard design for all the newer locomotives (AC motors and solid state speed control)?  Would anybody designing a revolutionary new motive power even consider or mention any other method of motor control?

[nkalanaga]

Actually, yes, they would still design traditional DC locomotives.  AC is most popular for drag freights, because the motors won't overheat as fast at very low speeds, and since the speed is frequency-controlled, wheel slip is greatly reduced.  For locomotives that spend most of their time well above the continuous speed, and for switchers, DC motors are still popular, because the electrical system is much simpler.  No inverters or other complicated stuff, just an alternator, rectifiers, and a throttle.