What does 4-8-4 or 2-8-8-2 mean?

Model Railroader General Discussion (Model Railroader)
1

Ok, here goes my first question.

What does the number designation on steam engines mean? In other words what does 4-8-4 or 2-8-8-2 mean?

I have searched the forum for the answer but to no avail.

2

Wheel arrangement of the locomotive from the front backwards.

4-8-4 is 4 pilot wheels, 8 drivers and 4 trailing truck wheels.

Here is a link http://www.railway-technical.com/st-clasif.html

3

The first number is how many pilot wheels there are (front small wheels). So being 4 there are 2 axels with 2 wheels on each. The middle number is the amount of drive wheels(the biggst ones). Being 8 it means 4 axels withe 2 wheels on each. And the last number would mean the amount trailing truck wheels(the smaller rear wheels. So being 4 there are 2 axles each with 2 wheels.
Does this help?

4

Thanks for the info. I figured it had something to do with the wheels but was not sure just what.

Simon, thanks for the web link. It has a lot of interesting info.

5

www.ztrainman.tripod.com/