This is something that is already somewhat old but currently valid, but some of you may not be familiar with.
In next link you can find almost all information about TSC design parameters. But what may be important for you is not designing, but understanding the parameters and the units they are being used. The right tool we have at our disposition to access design parameters is TS-Tools, which allows to open and edit .bin and .xml files.
An editor like Notepad++ also helps you out with .xml files reading and editing.
This is the link: http://tscdevdocs.co.uk/
The link is based in http instead of https, so you will probably will get a non-secure warning.
The site can also be accessed from DTG portal here (you need logging in):
https://live.dovetailgames.com/live/live/discover/welcome-to-the-developer-portal
And the entire library can be downloaded here to store it in your PC (or in the RWA file library---I don´t think it is here yet (Chacal?)).
http://tscdevdocs.co.uk/reference-manual/downloads.html
It is important to understand that many parameters are TSC native and not part of real world specifications. For example, in the steam locomotives boiler parameters there is something called Idealfiremass, which is not used in specifications of steam locomotives:
http://tscdevdocs.co.uk/reference-manual/blueprint-editor/steam-simulation-blueprints/subsystem-setup.html
I hope this will be useful.