The only Dash 7 I've been on is a B23-7 rebuilt from hi-nose to lo-nose so I don't know if they change the toilet location or not. I checked my photos and the toilet was behind the rear cab wall entered from the cab. I was impressed at the time because you could sit on the can, open an access door and pull the battery switch. The electrical cabinet was split with the reverser and contactors in a cabinet underneath the left side of the cab extending back a ways, accessed from the outside. The circuit breakers and some control switches were on the back cab wall, the electronic control modules and low voltage relays were behind the toilet compartment, accessed from the engine room.

When you really start looking at the technical aspects, it's sometimes amazing how many electro-mechanical changes were made some drastic enough they almost deserve a change in model designation.

For instance, GP35s had an entirely different frame change in the middle of production, the GE Dash 7 line changed their wheel slip system and transition (to alternator) in the middle of production, the SD45 had a major excitation control change to simplify transition, the GP39-2 shifted its major engine room components back a ways, etc.