What does the designation "trail" mean?

[lvlender]

I am updating broken *.con files in my consists folder ( a very tedious process!). I am regularly coming across locomotives that have a "trail" designation attached to the file name as follows...

Engine (
Flip ( )
UiD ( 2 )
EngineData ( NS_D9-40CW_9386TRAIL "SLI NS engines" )

How does this differ from the standard locomitove file or AI locomotive?

[niknak]

I believe it means they are designed to be put behind the lead engine in a consist - rather like an AI engine in that there is no cabview.

[cuontv]

In older sets of MSTS locomotives SLI and others designated locomotives as such to indicate they were to be used in the Trailing position of a locomotive consist, i.e, the second, third, fourth, etc., position in a lashup following (or trailing) the lead unit. A locomotive designated for this might not have a cabview associated with it (so you can't sit in the cab) or the lighting section may be atonated to reduce computing power needed to process the ENG file. No need for a headlight lighting section in the ENG file if the unit always operates as a follower.

You might also see designations as XXXXAITRAIL by some manufacturers to indicate these locomotives are setup for AI Trailing functions only. It's all to reduce computer processing load.

Now that computers are more sophisticated and with the advent of OR, I think the AI and TRAIL designations have dissappeared on newer models, but I could be wrong. Hope this makes sense.

-C.U.onTV

[geepster775]

You are not wrong. AI and Trail are obsolete features outside of MSTS.

[lvlender]

You are not wrong. AI and Trail are obsolete features outside of MSTS.

I get it now that you explained it. Thanks to all that responded.😉