Probably the most essential work car on any trolley company’s roster was the line car, or tower car. Because the wire is exposed to constant wear from the wheels and shoes that collect the power to run the cars and the forces of man and nature, regular maintenance was vital for the smooth operation of the system. The line car was often the only means of accessing the problem.

Car M210 was built in 1940 at Pittsburgh Railways’ Homewood Shops, using components salvaged from two other cars. Its trucks and control equipment came from car 4306, a double-ended low-floor car very similar to museum car 4398. Its tower equipment was transferred from line construction car M211.

The car embodies many special features which make it very versatile. The tower or platform on the roof hydraulically raises and lowers to adjust to a comfortable work height, and will also swivel to allow work on poles or the wires on adjacent tracks. Inside, the car carries a 5,000-foot spool of wire. Through a special power collector on the wire reel, the line car is capable of operating while threading out new wire. To facilitate this operation, its control circuits are equipped with a special slow speed mode.

M210 has been in continuous service with only cosmetic changes to its basic appearance since 1940. Radio equipment was added to the car in the 1970s by Pittsburgh Railways’ successor, Port Authority Transit (PAT); in 1989, computerized control equipment was added to make the car compatible with the new system on the light rail lines in Pittsburgh. M210 was declared surplus in 1995 by PAT and donated to PTM, replacing the existing line car 2 which was converted from a double truck Philadelphia Transportation Company snow sweeper by Museum volunteers in the 1970s in lieu of having M210. This car was subsequently traded to the New York Museum of Transportation where it continues in use as an overhead line car.