How does one test for PTC, ATC, ATS, ET AL, when not on the main line?

Dominic Mazoch posted:

I was going to ask this in the resent thread about the 844, but it would really be "off topic".  But if a locomotive needs special cab equipment like PTC, ATC, ATS, ET AL, how does one check it in a terminal or engine facility off the main line?

The UP has portable "test loops" at pretty much each locomotive terminal, thus once activated, the cab signal equipment, or the former CNW ATC equipment can be completed tested, prior to dispatching the units as a "leader".

Thanks.

Now, do ALL UP locomotives have this equipment, or a select group.

Dominic Mazoch posted:

Thanks.

Now, do ALL UP locomotives have this equipment, or a select group.

Yard engines do not.