The "Moving Beam" Car
In the 1870s and 1880s (before the electrification of street railway lines), streetcar operating companies were constantly working on methods to run the cars without using animal power. Steam power wasn't usually acceptable, because steam locomotives were too noisy for street railway operations. Anybody with an idea for a propulsion system could get an interview with a streetcar company.
One of the ideas that made its way to New Orleans was the "moving beam" streetcar, seen here being tested near Canal Station. The operator on the left-hand side of the photo would crank up the weel at the end of the car, which would move counterweights and turn gears, which would in turn move the overhead beams. The beams would then turn the large wheel at the back of the streetcar. That big wheel had blocks which came in contact with the ground. As the blocks pushed off on the ground, the car moved forward.
There were a number of problems with this propulsion method. It relied on the operator to occasionally crank it up, which could make for a long work day. The propelling wheel (which looks to me like a land-locked paddlewheel) did not adjust or compensate for irregularities in the street or gorund (such as potholes), so the ride could be bumpy.
The New Orleans City Railway Comnpany never took the "moving beam" car out of the testing phase, so the mule-powered "bobtail" cars continued to be the mainstay of Canal Street operations until electrification.