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"Truck Repairs Put on a High-speed Basis" (1928)

ELECTRIC RAILWAY JOURNAL · Vol. 71, No. 18 · May 5, 1928 · pp 729-734.

Truck Repairs Put on a High-speed Basis

By Clarence W. Squier, Associate Editor Electric Railway Journal

Installing a pair of wheels in a truck in the intermediate repair section of the Coney Island shops. Repair work is done with the trucks on stands, to raise them to a convenient height for the workmen.

In the intermediate truck repair section of the Brooklyn-Manhattan Transit Lines' Coney Island shops repaired trucks are substituted immediately for those removed so that cars are not withheld from service.

When repairs to car trucks of the Brooklyn-Manhattan Transit Lines are necessary between regular overhaulings, they are made in the intermediate truck repair section of the Coney Island shops. The methods used are quite different from those common in other railway shops in that trucks are changed from one car body to another. Cars whose trucks require repairs are not withheld from service but are brought into the shop, the defective trucks are removed and replaced by others in good condition, and the cars are then returned to service without delay.

In considering this method it might appear that a large number of spare trucks would be needed. On the contrary, as the work is carried out on the Brooklyn-Manhattan Transit Lines, only six spare trucks have been found necessary, besides those actually required for car bodies, to take care of the truck repairs for the 900 subway motor cars, 50 subway trailer cars and 121 triplex units which are operated on the system. The reason is that trucks from cars which are in the shop for general overhauling and repainting are used to carry out truck repair work. This releases enough trucks so that twenty can be placed in the repair section and worked on at one time.

The facilities and methods used make it possible to carry on the truck repair work continuously and to organize the shop forces along the most effective lines. Returning cars to service quickly or making them available for service without delay is the feature around which the plan for repair work has been built. Any additional cost for spare equipment to carry out the program will be met several times over by the added revenue from the increased service obtained from cars.

The intermediate truck repair section is 480 ft. x 80 ft. This long section has an electric drop pit transfer table, which runs across its center. All trucks enter and leave the repair department by this transfer table, being handled to and from the twenty repair stands on which the work is done by two 15-ton, overhead-traveling, cranes. Ten of the truck repair stands are placed in each of the sections on either side of the transfer table. Along the two sides of the section are numerous cabinets, material racks and bins, workmen's benches, machine tools, rivet heating furnaces and miscellaneous equipment used in the repair work.

Motor leads and brake rigging of trucks which are to be repaired are disconnected in the inspection shop, which adjoins the truck repair section, so that removal is easy. Most of the subway cars of the Brooklyn-Manhattan Transit Lines are operated in groups of three. These are handled as units, being kept together and shopped at the same time. Whenever it is necessary to remove a particular truck the three cars are brought in.

The track over which the cars come in has an electric drop-pit table, supplied by the Whiting Corporation, Harvey, Ill. This is operated in conjunction with two special overhead cranes supplied by the Box Crane & Hoist Corporation, Philadelphia, Pa. The cranes have L-shaped hooks to support the car body while a truck is removed or replaced. When removing a renter truck from an articulated unit it is necessary to support the ends of two car bodies at the same time, so there are two 15-ton overhead cranes with two sets of supporting arms. The crane equipment extends over the truck removal track and is fitted with trolleys and appliances for convenient operation. The cranes are equipped for longitudinal and transverse movements but not for vertical motion as this is taken care of by the drop-pit table. The entire equipment for the overhead cranes and the electric drop-pit table is controlled electrically from a station on the floor alongside the drop pit.

The electric drop-pit table is supported on four upright screws. The lower ends of these screws rest in blocks in a wheeled truck which runs on a track in the pit. Motors for the raising, lowering and transverse movements are mounted on the table, but are controlled from a stand on the floor of the overhauling shop. Locking bars take the live load while the train is moving across the table.

After the train has been placed so that the truck to be removed is in the center of the table, the table is elevated enough to give clearance for easy insertion of the body holding hooks from the crane. The locking levers are then released. There is an electrical interlock so that the table cannot be lowered until the locking bars are entirely unlocked or locked. The table is then lowered to give clearance for removal of the truck, and then, along with the truck, it is moved transversely.

As the transfer table has two surface tracks a truck in good order can be placed on one track before a train is brought in while the truck being removed will be placed on the other track. The transverse movement of the drop-pit table which takes out the defective truck then brings the second truck into position, so that the table can be raised again and the new truck placed in position under the car body. The shop section adjacent to the pit table has three short spur tracks which line up with those on the table in either of its two stationary positions. Trucks can thus be run on and off the table and left on the spur tracks until it is convenient to handle them with the traveling cranes. A truck can be dropped out of a car and a new one installed in a very short time without uncoupling cars.

Control equipment has been ordered for this section so that trucks can be moved to and from the transfer table under their own power. This equipment consists of contactors and resistors controlled from push button stations alongside the tracks. A single lead will supply power to the truck to be moved.

At present the truck repair section has a working force of 20 men during the daytime and 21 men at night and the section repairs an average of from 20 to 25 trucks per day. Running repairs are made only and no general overhauling is attempted. Some of the defects which require removal and repair of trucks are grounded or flashing of motors or armatures, burned off motor leads, grounded brush-holders, worn wheels or those with sharp flanges, worn spring-plank hangers, worn shoe head hangers, broken or worn axle bearings, loose rivets and worn pedestal liners.

A simple but effective record system is used for notifying the shop that repairs are required, for ordering in the cars, for supplying information for a permanent record of truck or motor changes, and for showing the class of work done during each repair period. Two card record systems give immediate information as to the location of any particular truck. One of these is arranged by car numbers and the other by truck numbers. The car cards show the trucks in and out together with dates. The truck cards give the number of cars in which the trucks are installed or removed together with date. The drop table operator records the trucks as they are removed and installed. There are two sets of books so that one may be worked on in the office, while the other is in use at the transfer table. These books are arranged with columns for the number of the truck, the car from which it is removed, the time of removal, the number of the truck which is used for replacement, and the time that it goes under the car.

Attention has been given to labor saving tools so that the men may work efficiently, and so that many of the operations may be performed by a single man, where otherwise several would be needed. Many devices have also been worked out to assist in doing the work quickly and with few men. One example of such equipment is a lever device which is used to compress the coil spring underneath the truck frame and on top of the journal box while a binder bolt is put in position under the journal box. This device, shown in an accompanying illustration, has a block which rests on the truck frame. The short end of the lever has a link with a hooked end which fits into the inside of the wheel rim. A man pushing down on the extreme end of the lever can then compress the spring sufficiently so the binder bolts can be put in position.

Fixtures are used for seating the elliptic springs in position in the spring plank and also in the bolster. To get them in place they must be compressed. Stirrups over the ends of the springs and with a chain connection between the two, the overhead crane lifts and so compresses the springs and they can be forced into place readily.

An accompanying illustration shows a stand that is used for supporting bolsters during drilling. This stand rests on the floor alongside the drill press with the center of the holster resting on the top. The workman can then rotate and move it into a position for drilling.

A crew of three men does the riveting. When not at work on the trucks these men make up spare ends for trucks, transoms, etc., so that these parts are ready to be installed whenever a defective one needs replacement. Packing of journal boxes is speeded up considerably through the use of a pneumatic gun with a packing iron. This method also results in tighter packing and is less tiresome to the workman.

Journal bearings and motor axle bearings are fitted in the truck repair section. Each bearing is fitted to its particular axle, but to speed up repairs bearings are bored out to certain standard sizes that are used most frequently. The diameter of a new motor suspension axle seat is 6 1/2 in. and the minimum diameter to which it is permitted to wear is 6 1/8 in. The bore of bearings will then vary between these extremes. The man responsible for the fitting of bearings tries to keep at least one bearing of each size on hand. These bearings are marked carefully with the exact bore and are stored in locked cabinets at the side of the truck repair section.

As axles come out of trucks, the bearing fits are trued up if they have worn tapered to any appreciable extent. There are thus two general classes for bearings. First, to fit new and worn bearing seats, sizes 6.550 in., 6.540 in. and 6.525 in. are used most frequently, and second, to fit turned and worn bearing seats sizes 6.490 in., 6.468 in. and 6.438 in. are needed most often. In fitting axle bearings the bore is kept between limits of 0.0025 and 0.003 in. per inch diameter larger than the axle seat.

To insure a correct fit, motor axle brasses are clamped in position between the motor frame and the axle cap with the latter bolted tightly. The bore is then gaged carefully, after which the axle caps are taken off, the axle put in position and the bearings and axle caps then installed permanently.

Sometimes it is found that the bore is reduced in size, because of the squeezing, as much as 0.006 in. Axle bearings are of bronze without babbitt lining. The manufacturers furnish them finished to correct dimensions on the outside and rough-bored on the inside.

Axle bearings are bored in the truck repair section with a vertical boring machine, as bearings can be mounted for machining more quickly and conveniently in a vertical position than horizontally. The bearing revolves instead of the boring bar and this results in more accurate machining.

Truck journals have a diameter of 5 in. when new and are not permitted to wear less than 4 3/4 in. Only one size of journal bearing is used. This has a 1/8 in. babbitt lining.

The drop-pit transfer table has a platform that raises and lowers. Longitudinal motion is provided by moving the entire table on rails at the bottom of the pit.

For removal of trucks, cars are brought into the repair section on a single track with a drop-pit transfer table at the center. Two overhead cranes operate in conjunction with the drop-pit transfer table for truck removal.

The entire operation of dropping out a truck is controlled from a station alongside the drop-pit table.	The transfer table is provided with two tracks so that one truck can be moved into position for installing at the same time that another is removed from the car.

Overhead traveling cranes handle trucks between the transfer table and the truck repair stand.	Workmen guide the motor so that the motor axle suspension seats properly as the motor is handled by an overhead crane.

Bolts are installed under journal boxes quickly by means of a lever attachment that compresses the spring between the truck frame and the top of the journal box.	Stirrups fit over the ends of elliptic springs and lifting by the crane compresses them so that they fall into position readily.

With a truck bolster on a special stand the drilling for filler blocks is done quickly.	The riveting crews make up ends for truck frames and bolsters when not working on the trucks.

Journal boxes are packed with a pneumatic gun. This method is less fatiguing to the workmen and gives tighter packing for the waste.

Motor suspension axle bearings are kept in cabinets and are marked with exact dimensions so that they can be fitted readily as needed. Accurate gaging is done on a bench.

The two halves of axle bearings are bored out at one operation in a vertical boring mill.

Sources: Electric Railway Journal, McGraw Hill Company, Digitized by Microsoft, Americana Collection, archive.org.