N trucks and couplers

[Lackawanna Consortium]

What is the difference between roller bearing trucks and friction bearing trucks. Thanks  Paul

[ACY]

Roller bearing is used on all equipment modernly, all older equipment in the steam ear had friction bearing. Most railroads either will not transport anything with friction bearing trucks or charge a very large fee to do so.
Friction bearing trucks require periodic lubrication, so the bearings usually were easily accessible within the journal boxes.  Roller bearings are sealed units, and require no additional lubrication during normal use.

[spookshow]

Everything you ever wanted to know about trucks (and then some) - http://www.spookshow.net/trucks/trucks.php

-Mark

[Lackawanna Consortium]

Thanks guys for your answers. It was exactly what I was looking for.  So 50 70 and 100 ton trucks would be according to the load and size of the car?

[spookshow]

That's correct.

-Mark