What is the purpose of full body cowl?(sd50f)

[Anonymous]

Why do the engines cn bought in the 80's sd50's and sd60 have full body cowling like the f unit of years past? Any insight ????

[BentnoseWillie]

The full-cowl carbodies developed by CN were intended to expedite turnaround servicing in winter. The full enclosure with an interior walkway allows shop forces to do minor work from inside the carbody, rather than having to clear snow & ice from the doors of a hood unit to access the engine compartment. CN's design features tapered notches behind the cab for rearward visibility, leading to the nickname "Draper Taper" in honour of Bill Draper, CN's Superintendent of Motive Power at the time and the driving force behind the idea.

CN purchased the following cowl-bodied locomotives:

HR616's (2100 series) from MLW

SD50F's and SD60F's (5400 and 5500 series) from GMD

C40-8M's (2400 series) from GE

In addition, BC Rail and the Quebec North Shore & Labrador bought C40-8M's. QNS&L's were tacked onto a CN order, and built to CN specifications. CP Rail's last order of SD40-2's also featured a CP version of the cowl carbody with a 3-window cab - the SD40F-2's, alias the "Red Barns".

The extra cost of cowl carbodies wasn't sufficiently offset by savings in turnaround maintenance, so CN changed their first order of C44-9's (which were ordered as C44-9M's with the cowl carbody) to a larger number with the standard GE hood and the CN-design 4-window cab, at the same total cost. Since the second order of C44-9's , CN have purchased modifications to the builder's own cab designs, with modifications such as windowless nose doors to meet CN's safety specs.

[Anonymous]

Thanks,that was very informative I was guessing it was something along those lines.