172 TRE's which way

[leew88]

Seems like a stupid question but which way around do they go? The way they came off and others (from google pics) look backward

the angle from the rack to TRE is much tighter and for the life of me cant see why

 

[AlexW]

I do remember thinking they look backwards all the time.

Firstline ones say left & right on them.

I wonder what the reasoning behind it is.