Post by Steven Dale
San Francisco Cable Car
The exception to Detachable Grips are what I like to think of as Attachable Grips. This concept is best exemplified by the familiar San Francisco Cable Cars. I will not go into a long description about the technology. Instead, I’d like to point you to Joe Thompson’s Cable Car Guy website which does an excellent job of explaining the technology.
In summary, the vehicles attach themselves to a below-grade cable by “picking up” or “gripping” the moving cable. This is unlike virtually every other cable technology in the world. In typical detachable systems, vehicles are attached, detachached, slowed and accelerated automatically by off-board mechanisms located within terminals and stations.
Not so in San Francisco.
Gripman
San Francisco cable cars have virtually no automation. Attaching, releasing, braking and accelerating are all done manually by an operator known as a Gripman.
Beyond the desire to maintain a heritage technique, the Gripman is an essential feature of a San Francisco Cable Car given the system’s configuration and relationship to the city’s traffic.
Unlike all other cable transit systems, San Francisco’s cable cars operate within mixed traffic. This co-mingling of transportation technologies, makes automation a virtual impossibility.
The vehicles must be capable of “picking up” or “dropping” the cable at the near-instantaneous discretion of the Gripman.
As such, it’s best to classify the San Francisco cable cars as utilizing Attachable rather than Detachable Grips.
The difference is subtle, but has a significant impact on the systems’ strengths and weaknesses, a matter which I will get to in a later post. For the time being, an easy way to remember the distinction is this:
In Attachable Grip systems, attaching, detaching, acceleration and deceleration are executed on-board the vehicle in a non-automated manner.
In Detachable Grip systems, attaching, detaching, acceleration and deceleration are automated actions executed in stations or terminals off-board the vehicle.
Proceed to Grip Module, 4: Corners.
Return to Grip Module, Lesson 2: Detachable Grips
Creative Commons images David Hudson Floyd and johntrainor.
Want more? Purchase Cable Car Confidential: The Essential Guide to Cable Cars, Urban Gondolas & Cable Propelled Transit and start learning about the world's fastest growing transportation technologies.
Want more? Purchase Cable Car Confidential: The Essential Guide to Cable Cars, Urban Gondolas & Cable Propelled Transit and start learning about the world's fastest growing transportation technologies.
