Looking at photos or even builder's erection sheets just doesn't do the same thing.
Well therein lays the problem, on the Atlas GP40-2w and IM SD40-2w project,
neither manufacturer looked at GMDD plans for the cab. The cab is identical on CN GP38-2ws, CN/GO GP40-2ws (LWs), and CN SD40-2ws, there was no production change to alter any dimension in/on the cab thru the duration of production. (dont confuse this cab with MLW M420s or GMDD SD50s/60s or CP redbarns or F59phs...those cabs
are different)
Why did Canadian Prototype Replicas, a fledgling basement company from Breslau Ontario, get the cab dimensions perfect in 1983 when they produced their one-piece cab in styrene? (back when the cab didn't fit anything but the Altas/Roco GP40)
IM/Atlas would have been further ahead to 'copy' the Prototype Replica or Railflyer cab than to rely on some hack using a tape measure or 'eyeball' the model. Here's a list of the cab manufacturers and the problems with them:
Railflyer - perfect, albeit earlier releases have incorrect radius on windshield rubber
Canadian Prototype Replica (CPRep)- dimensionally perfect, slider windows are incorrect (but error hidden by sunshades)
H&D - resin copy of CPRep cab
Kaslo - resin cab, front windows too small. has interior tho.
Details assoc - nose too low, requires assembly.
Pacific Pike (brass) - nose too low, roof angle wrong.
Atlas - nose too long
Intermountain (pre-production) - nose too long, nose top slope, 'porthole' type front windows, RPP-like rough casting...just bad
