3d printing Could anyone help me with getting the scale right for 3D printing?

[Josef2000]

I do apologise if I'm in the wrong place! Also sorry if this message is hard to follow. English is my first language but I'm somewhat slow haha.

I'm hoping to create some 3D models of various rolling stock, signs and other miscellaneous pieces however I'm not sure how to accurately measure the model so it fits the appropriate OO scale.
Does anyone have any tips for 3D printing? I noticed that the smaller details can be tricky.
I'm hoping to create a standard coach first, and print out various sections such as the 'shell' and interior seating.

Many thanks,

Joe

[murrayec]

OO is 1:76 so your scale factor from 1:1 is .0131

Eoin