PU arrangements

[storminorman]

I've often wondered if there is rhyme or reason as to how PU's are arranged. Of course there is a reason, but this week I saw 7 power units leading the pack. Front unit was a Canadian Pacific, Soo, unknown, Iowa Chicago Eastern, CTX, Canadian Pacific,GITX . Also what reason is there if any for some to be turned 'backwards' in the lineup? I snapped a few quick pics off my cell phone but it has no zoom capability so the pics are not nice close ups. I also need to read FAQ here to see how to post pics as well. I'll try and 'attach' a pic below here....

 

[CSXYM]

There is no specific reason as to the direction of the engines other than if it's power that will turn back on another train, then they would want a good one to lead in the opposite direction (preferable a wide-body that would afford better collision protection, A/C equipped, more quiet, etc.) Usually, the middle units are just as they line up from other consists, only we (CSX) like to place DIT (dead-in-tow) units at the rear of the consist. Then if tonnage allows you to isolate/shut down power, you wouldn't have to pass through the dead units to get to the units to be isolated/shut down.

 

[storminorman]

Thanks Walt...that's interesting to hear. I never gave it a thought re: a wide body for better collision protection. Guess I figured the locomotive always wins in a collision regardless. When you say wider I suppose at a crossing accident it would tend to spread/deflect more away to the sides of a unit. Is there more?