Simple Circular Motion question

[StephenP91]

Homework Statement

There is a train traveling along a circular track. Which rail does the centripetal force act on (Inner or Outer) and what 2 factors determine the stress on each wheel.

Homework Equations

The Attempt at a Solution

So I was thinking it might be the outer, but I am not sure and as for the wheels, I imagine one of the factors is the train's weight, as for the other, not sure.

 

[Ambidext]

Homework Statement

There is a train traveling along a circular track. Which rail does the centripetal force act on (Inner or Outer) and what 2 factors determine the stress on each wheel.

Homework Equations

The Attempt at a Solution

So I was thinking it might be the outer, but I am not sure and as for the wheels, I imagine one of the factors is the train's weight, as for the other, not sure.

I would think it's the inner track that provides the Fc. Not sure either.

Stress on the wheels would be the weight of the train and the static friction.

 

[Quinzio]

Homework Statement

There is a train traveling along a circular track. Which rail does the centripetal force act on (Inner or Outer) and what 2 factors determine the stress on each wheel.

Homework Equations

The Attempt at a Solution

So I was thinking it might be the outer, but I am not sure and as for the wheels, I imagine one of the factors is the train's weight, as for the other, not sure.

The correct answer is: it depends how the wheels are made.

This is a common train wheel
[PLAIN]http://img690.imageshack.us/img690/3334/14149522.jpg

If the holder is internal (see picture) as in all trains, the track that generates the centripetal force is the outer.
If the holder is external, the inner track generates the centripetal force.

There is a reason why the holder is internal, why ?