Sunday, September 13, 2020

Motor Coach # 4073

Motor coach # 4073 was 1 of 104 last design heavyweight multiple unit (MU) coaches built for the New Haven Railroad. Built by Osgood Bradley during 1926 this car is 1 of the 40 trailer coaches of this round roof design to be converted to a powered motor coach using Westinghouse electrical components at the New Haven's Van Nest shop in the Bronx, New York.

Although these motor coaches were rated to pull 3 unpowered trailer coaches, on the Danbury Connecticut - South Norwalk Connecticut shuttle only a single motor coach was used for that scheduled train during the era of the layout.

           Motor coach # 4073 at Danbury Connecticut station 1957. Photo by J. W. Swanberg     

             Again at Danbury this time 1959. Photo by J. W. Swanberg

Model #4073

Custom Brass had at one time offered a three car set of these MU cars consisting of 1 powered motor coach and 2 trailer coaches. Like the prototype photos above, only the motor coach from this set will be used on the layout to model the Danbury - So. Norwalk shuttle.

The body shell from the Custom Brass set appears to be accurately modeled although it lacks some roof and car end details that will be added during the build.

The used Custom Brass set purchased was well cared for but ran poorly with the factory motor and gears that had cracked from age. The motor powering the model filled a good portion of the interior seating area and was unrealistic when looking thru the side windows.

Stanton Drives from NorthWest Short Line will re-power the model improving the running qualities and eliminate the unsightly motor in the interior.

The greatest shortcomings of this model are the lack of interior but more importantly correct prototypical underbody details, this is where the most time and effort will be consumed during this build. 

Below is the motor coach as purchased with the pantographs and original drive motor removed from the interior. 

Re-powering the motor coach

Two Stanton Drives are used for the re-power. Although unlikely for this layout, the decision to use two drives is incase pulling of trailer coaches will be desired in the future.

The Stanton Drives are below, the molded on coupler mounts (left) will not be used and cut off  (right).

The first problem to solve during this build is when the Stanton drives are mounted underneath the original brass floor plate the ride height of the body shell is too high and the plate is not level end to end, therefore a new floor plate with wells for the drives to recede into is required to lower the ride height. The replacement floor plate below is made from .040" styrene, recess openings are cut into each end to accept the new drives.

The drives will need to recede .030" thru the floor plate for the correct ride height of the body shell and couplers. Below a .030" styrene spacer is glued to each side of the opening on the interior side of the replacement floor plate. 

A .040" styrene drive mounting plate is glued on top of the .030" spacers and a hole to accept the center pivot point of the drive is drilled. The open area to the left of the mounting plate in the below photo is for the drive wiring to move freely when negotiating curves.

The interior side of the original brass and replacement styrene floor plates are compared below.

The styrene floor plate is flexible end to end at this point when not mounted to the body shell. The body shell below has a brass angle soldered to the inside of both car sides to mount the original brass floor plate.

When the new styrene floor plate is mounted onto these angles as seen below it becomes sufficiently stiff enough to replace the brass plate.

Body shell mounted on replacement floor plate with Stanton drives installed to check ride height.