I assume that this is a drawing of a G601 as it does't have recessed handrails, it has the straighter exhaust, and it doesn't have vacuum bags or marker lights. However it doesn't have the air horn which the 601s did have and the 611s didn't have (since the 611s had vac loco brakes)
The below details are for G611s. If you're making a model, remember to add the exhaust whistle (video of whistle in action) and the small electric horn at the top of the front of the cab as well as the obligatory can of easy start. If you want any measurements, please let me know and I can do it in person on G617