Re-evaluating Gas Turbine Engines for Railway Propulsion

[charlie_hebdo2]

In a different setting:

*Large cruise ships are primarily powered by [diesel-electric propulsion systems.

• Gas Turbines:Some ships, particularly midsized ones, use gas turbines to generate electricity, often in a hybrid system with diesel engines.
• LNG Power Plants:New cruise ships are being built with LNG power plants to reduce their carbon footprint, though they still function within a diesel-electric system.
• Hybrid Systems Some ships combine different power sources, such as diesel engines and gas turbines, to provide power for both base load and peak demand situations.

[Woke_Hoagland]

@D.Carleton

Back last century when I was but a young nuke I wondered out loud why our (steam) turbine/generator set didn’t have roller bearings.

The rotor turns too fast. Not only are hydrodynamic bearings more stable, they can be made with one face elastomeric to absorb high-frequency vibration and tolerate contaminants in the lubrication that might otherwise act as asperities penetrating the oil film and scoring the journals or thrust faces. By analogy, consider why rolling-element bearings are seldom found in combustion-engine turbochargers.

The better approach when using ceramic turbines has been magnetic bearings, active control for which has been available for decades and is now relatively costed-down. This provides effectively no wear in steady-state operation, and it becomes possible to use something like the self-lubricated bearings in the small Williams cruise-missile turbofans as protection against interruption of bearing integrity or excessive deflection from shock.

As a note: it was not uncommon for steam-turbine dynamos on locomotives to have ball bearings on the common shaft.

[Erik_Mag]

@charlie_hebdo2

How efficient were the variously fueled rail turbines compared to diesel in past?

The 4,500HP GTEL’s burned about 450 gallons per hour at full throttle and about 200 gallons per hour at idle. A 4400 HP diesel burns around 200 gallons per hour in run 8.

[Erik_Mag]

@D.Carleton

The advantage of the turbine in my proposal is the lighter weight, smaller size would make more room for batteries.

I think a gas turbine battery hybrid would make one heck of a commuter locomotive, especially if the batteries were sized to allow adhesion limited tractive effort to say 60 - 70mph or higher. This would allow for much of the energy used for acceleration to be recovered with regenerative braking. One could get faster schedule speeds and reduce fuel consumption.