Solar stirling locomotive

[James80]

I've been pondering building a locomotive engine which runs using a stirling but using the 'foam' and heat method rather than lenses.
Now this sounds impossible as I doubt you'd get enough torque.
Anyone know how much torque you are likely to need to run a small locomotive? Essentially I reckon it comes down to the amount of heat difference that you can produce, so that you have the ability to drive such a thing.
I know they do small cars with gamma engines, not sure what fuel they run off.
But where are the limitations of using a solar energy?

[KTD1]

I have only built a couple small engines. You need a small temperature differential in a lot of gas or a big differential in a little gas. The size to horsepower ratio for low temperature Stirling engines is a serious problem.

How much power would be required is directly related to how fast one wants to go. My guess is that you would need a lot of collector area.

The best way to find out is to try!

[James80]

Sure, one idea I have is to use a fan and heatsink on one side for cooling. Obviously this would be solar power, just looking at the panel sizes for voltages enough to drive a small fan makes you realise everything is a little impractical.