I'm wondering why knuckle couplers seem to be found only on railroad cars. Why did the Shaker Heights Rapid Transit Lines and the CTS Rapids of my youth have lighter-weight couplers that looked more like fish hooks rather than knuckle couplers? Apparently they worked just as well, but why weren't lighter-weight versions of knuckle couplers used?
Do NYC or Chicago subway/el trains use the type I'm referring to?
Lastly, what is the correct term for this type of coupler?
Sounds like a Tomlinson coupler, which was widely used on electric MU's. These coupler were often paired with automatic MU and airbrake conections, saving mucho time when assembling or disassembling a train.
The PE used these on the "Hollywood" cars, the PE 700's at OERM have remnants of the auomatic MU connections.
FWIW, one of my great aunts lived about 1,000' from the SHRT lline in Shaker Heights.
The Chicago Transit Authority uses Ohio Brass Form 5 couplers, which are knuckle couplers with the electrical connectors below the coupler.
Chicago postwar L cars use Ohio Brass form 5 couplers, which are about a 3/4 size railroad style coupler with alignment pins on each side. There are no air connections since all Chicago cars are all electric. While all postwar Chicago cars can be physically coupled together, there are electrical differences between various series that don't allow them to train together.
New York uses railroad size couplers. Many series, including all in current use, have automatic connection capablity.
The Tomlinson was widely used in transit and interurban applications. Cleveland Transit used them for trailer operation with streetcars. Box construction with the knuckles inside means that the couplers stay together with both vertical and horizontal movement. NICTD's ex-South Shore operation in Indiana uses Tomlinsons on new equipment (CSS&SB used railroad couplers). Adapter couplers are used when the cars are pulled by locomotives in emergency situations.
Early transit cars and interurbans often used Van Dorn couplers, which were more or less link-and-pins. Chicago used a variant from Sterns and Ward that allowed for automatic coupling on some lines.
I hazily remember the older Philly Frankford Elevated cars I was riding on in the late 1940's and very early 1950's had something resembling Link & Pin.
rcdrye Van Dorn couplers, which were more or less link-and-pins.
So the couplers I had in mind were termed Tomlinsons, huh? I'm glad to learn that.
Cleveland's Van Dorn Iron Works for generations turned out things like park benches, jail bars and doors, and now, I'm guessing, link and pin-type couplers for traction equipment. Who knew?
Thanks for the replies.
rcdryeThere are no air connections since all Chicago cars are all electric...
How did they brake/stop the cars?
Philly Frankford cars had Tomlinsons. Van Dorns were obsolete by the late 'teens, even though some remained in service into the 1950s.
MidlandMikeHow did they brake/stop the cars?
Chicago's first generation of postwar L cars were all-electric PCC cars, either built new or with new bodies and components from postwar Chicago streetcars. They used dynamic braking down to very low speed, then a band brake on the motor shaft to complete the stop. Later cars, beginning with the 2000 series, use slightly different arrangements, but the operating principles are the same.
Illinois Central used Tomlinson couplers on its heavyweight MU cars and also on the Highliners.
rcdryeChicago's first generation of postwar L cars were all-electric PCC cars, either built new or with new bodies and components from postwar Chicago streetcars. They used dynamic braking down to very low speed, then a band brake on the motor shaft to complete the stop. Later cars, beginning with the 2000 series, use slightly different arrangements, but the operating principles are the same.
Would battery backup stop the train in a power disruption?
MidlandMike rcdrye There are no air connections since all Chicago cars are all electric... How did they brake/stop the cars?
rcdrye There are no air connections since all Chicago cars are all electric...
So how do the cars stop when there is a train separation ?
By looking for a loss of continuity in one or more of the lines in the MU connection is my guess. This could be even quicker than the response of an automatic air brake to a break in two.
erikem By looking for a loss of continuity in one or more of the lines in the MU connection is my guess. This could be even quicker than the response of an automatic air brake to a break in two.
MidlandMikeWould battery backup stop the train in a power disruption?
PCC cars had three types of brakes. Primary was dynamic where the motors were made into generators that disipated their energy into the accelerator's resistor grids. This energy was not returned to the 600 Volt trolley wire, so dewiring did not affect braking. Second was brake drums on the motor shaft that had solenoid operators that were held released by battery power and applied as the cars speed dropped below about five mph to make the final stop. (Dynamics have little braking power at slow speeds) Third were magnetic track shoes which were located on the trucks between the wheels and were for emergency braking. Now if the battery failed, the drum brakes applied. Battery was charged from a motor generator blower set which had the blower for the heating and ventilating system. Generator besides charging the batteries also powered all the lights and any other auxiliaries. At the trolley museum where I an a member, these can be maintenance prone because they are in constance operation when the car is active.
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