They have a 91-year-old electric railway car up and running

Electrical Apparatus, Jul 2002 by Satrom, Megan E

Clang, clang, clang goes the trolley,

and they think it may run forever

DENVER-A group of local historians can toot their own horn, blow their own whistle, and ring their own bell. They're hoping that in a year, they'll also be able to carry passengers in their own fully restored trolley car.

Members of the Rocky Mountain Railroad Historical Foundation (RMRHF) are restoring Interurban No. 25, a nearly century-old electric trolley car that served Denver passengers until 1950, when streetcar use was discontinued.

As the only completely intact trolley of Denver's expired electric railway system, No. 25 has an impressive story to tell. The car, built by Woeber Car Co. of Denver, was put into service Feb. 11, 1911. It carried up to 52 passengers at a time between Denver and Golden, Colo., an old mining town that now serves as the mountainside entrance to the Denver metropolitan area, until 1950, when streetcar service ended in favor of buses.

When streetcar service came to a halt, the newly unemployed trolleys were sold to anyone who would buy them. Most of the car bodies were sold separately, but the Rocky Mountain Railroad Club (RMRC) paid $150 for No. 25's body and an additional $75 for the trucks and motors that went with it. While other car bodies became immobile fixtures on flat land, the RMRC continued to operate No. 25 for club excursions, until the overhead wire was removed in 1953.

After 35 years in storage sheds and museums, No. 25 found its current home in a shed in the Denver Federal Center, where members of the Rocky Mountain Railroad Historical Foundation (sister organization to RMRC) have spent 14,000 hours and $100,000 bringing the car back to its original state.

The RMRC was created in 1938 to educate the public in Western railroad history and to promote the present and future appreciation of railroad legacy. The RMRHF was created in 1990 to preserve historic railroad equipment and collect donations for the Interurban No. 25 restoration project.

Original hardware

Darrell Arndt, Chairman of the Interurban No. 25 Restoration Project, has been with the project since it began. He says this restoration project is possible for the club because the original hardware and electrical hardware came with the car. "We were blessed in this project," he said, "because we had all these parts."

No. 25, like most of the trolleys in its day, ran on four 50-horsepower Westinghouse d-c motors mounted on McGuire Cummings trucks. Although Arndt was not certain whether the motors were replaced between 1911 and 1950, he said the 600-volt motors were in good shape. Denver Electric Motor Service & Sales, Inc., a local service firm, took the motors apart, cleaned and tested them, and replaced the bearings. According to Arndt, it wasn't necessary to rewind them.

Each of the trolley car's motors, which originally received power from overhead wire through one of two spring-mounted trolley poles mounted to the roof of the car, rests between a truck frame and a gear-powered axle.

The speed of the car was controlled by 600-volt resistor grids, which ran in series with the motors. These serpentine iron grid resistors with mica insulators regulated the current going to the motors, which, in turn, reduced the speed of the trolley.

According to Arndt, control of the current to sections of resistors is accomplished by movement of the motorman's controller on the operating platform. "You wouldn't drive [a trolley car] like an automobile," said Arndt. "There are seven speeds, seven positions on the controller."

The K-35 Westinghouse controller aboard No. 25 was patented in 1892. "The controller works like a big rotary switch," said Arndt. As the operator turns the controller, different connections are made to vary the amount of resistance in the circuit.

The club completely disassembled and rehabilitated the original controller, which also varies the interaction between motors. Two motors in series, each operates at 300 volts. Paralleled, each motor sees 600 volts.

Tom Peyton, a member of RMRHF since 1991, said trolley operators would build up speed, then shut off the power and coast for an incremental speed. "Any speed other than full series or full parallel is an incremental speed, where power is going through the resistor grids and can only be done for short periods of time," said Peyton. "Trolleys did a lot of coasting."

The trolley's two-cylinder air compressor, driven by a 600 volt d-c Westinghouse motor of approximately 5 horsepower and 500 RPM, was in good shape and did not require much work. The original 200 amp/750 volt circuit breaker will continue to protect the car from shorts. And the manual gong bell, air-powered whistle, and brass air horn that made up the original warning system also worked without repair.

The car itself is wooden with a steel underframe. "When the car was built, the age of the wooden railroad car was starting to pass," said Arndt. In the transition to steel cars, companies built wooden cars with steel frames with truss rods underneath the car body to strengthen its backbone.