For many years, they have offered various chassis from switcher through hood to cab units with many options. Designs changed frequently through time. Earlier designs required a fair amount of adjustment for proper operation. However once broken-in they were excellent performers.
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EMD F-7 chassis with Pittman DC-70 motor and centrifugal clutch.
The clutch had internal rubber fingers which were thrown outward by centrifugal force as motor RPM increased. These eventually pressed against the inside of a cylinder with increasing pressure to produce the output torque. This, along with the flywheel, produced a quasi-momentum effect. When power was removed from motor, the fingers collapsed allowing free wheel coasting and flywheel momentum. The clutch requires hours of adjustment and periodic maintenance for good operation.
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EMD F-7 chassis with Pittman DC-91 motor with enough torque to pull the wall down.
The armature is almost large and heavy enough to provide a flywheel effect.
The more usual method was to drive one gear tower through universals from the motor and the second power truck through a lower universal shaft. An accessory inter-unit universal was offered to power succeeding unit trucks, accounting for the extremely large motor.
Using a square shaft, excellent universals were offered with fixed ball on one end and a sliding one on the other.
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Universal joints and shaft.
As an aside, on several occasions, while in Boston during the 50's and 60's, I tried to find their Park Square location in vain. All I found was a hobby shop near the opposite end of the Common, called Hobby Town, who very vehemently denied any ties with or knowledge of them. Apparently the firm later moved Florida with a new owner and designs for several years.
It is now owned by Howard Mosley of Bear Locomotive, 1361 Tuckerton Ave, Whiting, NJ 08759. (About 40 mi. from here.) Howard plans many new features.
BEAR LOCOMOTIVE
