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ELECTRIC RAILWAY JOURNAL · Vol. 71, No. 20 · May 19, 1928 · pp 805-812.
Wheel, Gear and Axle Maintenance in Brooklyn
By Clarence W. Squier, Associate Editor Electric Railway Journal
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| Pneumatic floor lifts provide a convenient means for turning wheels from the incoming and outgoing tracks to that serving the wheel lathe. |
For efficient maintenance of these parts on the Brooklyn-Manhattan Transit Lines, the most modern machine tools have been installed in the Coney Island shops. Careful grouping of machines eliminates rehandling.
Due to the large volume of wheel, gear and axle inspection and repairs on most electric railways, and to the necessity for repeating maintenance operations continually, the work is placed on a production basis more often than other railway maintenance procedures. As a result it is quite common to find wheel and axle work done in sections of the shop set apart for this purpose. The wheel press, boring mill, axle lathe and wheel lathe universally used for this work are usually grouped to eliminate unnecessary handling. With the advantage of a new shop at Coney Island with new machine tools, the mechanical department of the Brooklyn-Manhattan Transit lines has been able to perfect a most effective department for this work.
The wheel and axle department occupies a section of the shop 60x200 ft. Not all of the machine tools for which space is provided have been installed, but when completely equipped the department will include the tools listed in the accompanying table. A large section just east of the shop provides convenient open departmental storage for wheels, axles and shafts. This material is handled by overhead electric crane and electric crane trucks through doorways directly to boring mills or lathes for the machine work. Mounted wheels that come from the truck overhauling or repair departments are handled by overhead crane and enter and leave the section at the wheel lathe end. The entire department is also served by a 7 1/2-ton overhead traveling crane, while groups of machines have jib cranes, there being four of these in the department, each having an 18-ft. boom.
Handling Reduced to a Minimum. The number of times that wheels and axles are handled and the amount of handling equipment has been kept to a minimum by particular attention to location and grouping of machines. Wheel boring is done in the central part of the section. Each of the Sellers 48-in. car wheel boring machines has two built-in jib cranes. While one wheel is being bored another is picked up and held in position by one of the cranes to be swung on to the table of the mill, as soon as the boring of the wheel in the mill is completed. The other jib crane with the previously finished wheel in suspension deposits it on a truck placed alongside.
From the boring mill, wheels to be mounted on axles go to the Chambersburg Engineering Company double-acting, 400-ton, hydraulic wheel press. This machine is used also to press gears on and off. The double pressure heads make it possible to dismount both wheels from a trailer axle without the necessity of removal, after one wheel is pressed off, in order to turn the axle for pressing off the remaining wheel.
Hydrograph chart records are kept of each pressing-on operation. These are numbered consecutively for each day's work, and a notation is also made on each record of the wheel number, the man that fitted the wheel, and the diameter of its bore. Each day's records are put in an envelope and filed by dates. If it is necessary to consult the records for a particular wheel pressing later, the truck overhauling report furnishes the date wheels were changed and number of the wheels. The hydrogram records for that date with wheel number identify the particular operation. In addition, a book record for each pressing is kept at the press. When filled these books are filed.
Subway motor axles have a seat for wheels 7 7/18 in. to to 7 8/18 in. in diameter, and trailer axles have a wheel seat of 6 1/2 in. to 6 3/8 in. in diameter. Pressures for forcing wheels on must be not less than 75 tons nor more than 95 tons for motor axles, and between 70 and 90 tons for trailer axles. The wheel seat for a standard subway axle may vary 0.001 in. plus or minus. Wheels are bored 0.001 in. per inch of diameter smaller than the axle. This gives a pressing-on pressure of from 10 to 12 tons per inch of diameter. Complete information regarding wheel and axle fits for the different equipment in operation, pressing-on pressures, mating of wheels, scrapping diameters, etc., is furnished the wheel and axle department in blueprint form.
In mounting wheels it is the practice to have both wheels on the same axle of the same tape size. A special type of gage is used for gaging wheels. This has one side for gaging new and newly turned wheels and the other for gaging partly worn wheels. New and newly turned wheels are gaged from throat to throat, while worn wheels are gaged from back to back.
As the wheels used on the rapid transit motor axles have diameters ranging from 30 1/4-in. to 34 1/4-in., and gears have outside diameters of 25 in. to 27 in., it is possible to support the wheels at the rim for pressing off. A particular yoke has been supplied by the manufacturer of the press to go over the outside of the gear and fit between the rim of the wheel and the center frame of the press during the pressing. The yoke is suspended from a pipe framework with a roller support so it can be put into position or swung out of the way easily by the operator.
The Brooklyn system was a pioneer in the use of steel wheels for electric railway service, adopting them in 1905. Excellent results and substantial economies have been obtained. By concentrating all wheel and axle work at one point, under the direction of one man, every mile of service consistent with safety is obtained from the wheels.
Checking for Wear Systematized. The different maintenance foremen are expected to see that the wheels are worn to, but not below, the various scrapping dimensions which are furnished them in blue-print form for their guidance. New wheels for subway motor axles are 34 1/2-in. in diameter and can be worn to 30 1/4-in. Subway trailer wheels are of 31 in. diameter when new and can be worn to 27 in. When the wheels removed from the trucks are received in the wheel shop, they are checked carefully with gages to ascertain dimensions and defects. An inspector also checks the axles carefully and measures them to determine whether truing up is needed and also to make certain that the bearing fits on the trued-up axles are above the scrapping limit. If a bearing fit will not true up above scrapping dimensions the inspector paints it red and the wheels and axle are routed to the wheel press for removal of the wheels. The same inspector who inspects bearing fits also determines whether the wheels can be returned to service and indicates any work that is necessary. If it is found that the wheel will not true up to 1/4-in. above the scrapping limit it is marked for removal.
For steel wheel maintenance work the wheel lathe is an important and busy tool. At present, one high-powered lathe is doing the work. This was supplied by William Sellers & Company, Philadelphia, Pa. Three pairs of wheels per hour are turned out, on an average. Handling of the wheels is speeded up considerably through the use of pneumatic floor lifts and a hoist which forms a part of the lathe. The lathe has two turret tool posts, each arranged to hold four tools. There is a roughing tool for the wheel tread, a flange roughing tool, a combined tread and flange finishing tool, and a chamfering tool. The lathe swing is 42 in. and a 3/8-in. cut can be made at high speed. Through the use of an efficient clamping arrangement, wheels can be removed and new ones put in place for turning in two minutes. Only one man and a helper are assigned to the lathe. The helper assists in wheel handling, sweeps up chips, oils the machine, takes wheel measurements and does other work necessary while the wheels are being turned.
The wheels are rolled directly into position in the lathe on a track. Crossing this at right angles are two tracks used for the incoming and outgoing mounted wheels. There are two pneumatic floor lifts, one in the center of each crossover. The helper rolls a mounted pair of wheels along the incoming track to the crossover, steps on a button controlling the valve to admit air to the hoist cylinder of the lift, and the plunger raises the wheels free of the track. The wheels are rotated a quarter turn and then are lowered to the track leading to the lathe. The action is reversed to remove a pair of wheels after turning. This has proved a very easy and quick method for serving the lathe.
Each axle is carefully inspected and tested to detect any minute cracks that would be liable to result in breaking later. The axle, with its wheels in position, is wet with a bath of kerosene while on a test stand. The axle is then wiped dry and is painted with a paint of lime in a solution of one-third alcohol and two-thirds water. The alcohol causes the mixture to dry quickly. After numerous tests, this proportion was found to give a smoother coating than any other combination or composition. A crack retains some of the kerosene. This penetrates the lime coating quickly and leaves a brown discoloration so that detection is easy. Axles without wheels are dipped in kerosene and then wiped dry and painted with the lime. An accompanying illustration shows a crack at the end of an axle that was detected by this method. To get an idea of the depth of the crack the axle was turned down to the different diameters shown. Since this method of inspection was adopted no axles that have undergone this test have broken in service. It has been in use about 1 1/2 years. After testing, axles with wheels mounted are stored on racks to keep them off the floor until they are removed to other departments or shops for mounting in trucks. Wheel racks have four 3x4-in. angles arranged in pairs, each pair spaced wheel gage distance apart. The angles are fastened together by steel straps to form a rigid framework. Alternate pairs of wheels are staggered so as to take up a minimum amount of room. Each bearing seat has a protective covering, made of a number of wooden strips strung on small ropes. Each strip is about 1 in. square and of a length sufficient to cover the bearing surface. By tying the loose ends of the ropes together the covering is held securely.
Bearing seats which are worn tapered, out of round, cut or have rough fillets are turned in a gap lathe. For this work with wheels in position, two heavy duty American 24-in. by 14-ft. geared head engine lathes are used. The bed of the lathe has two gaps for the wheels, the swing in the gaps being 40 in. Each lathe has two carriages, one with two tool posts. With this equipment the two motor suspension axle bearings and one-truck journal bearing can be trued up at the same time.
New axles have bearing seats ^ in. in the rough over size when received from the manufacturers. They are turned and ground to accurate sizes in the wheel and axle department. For this work there are two groups of three machines each. In each group there are two 8-in. LoSwing axle lathes and one 12x96-in. grinding machine. Bearing fits are turned in the lathe to a size 0.015 in. to 0.018 in. larger than standard. They then go to the grinding machine and are finished accurately to exact size. The Low-Swing lathes were furnished by the Seneca Falls Machine Company to be used for axle and armature shaft turning. Their beds are 108 in. long. There are two carriages with three tool posts on each so that six tools can be used for cutting on the same post at one time. As a result of the use of these rapid production lathes the time necessary to finish axles has been reduced to one-fourth of that necessary with ordinary engine lathes.
An accompanying illustration shows one of these lathes turning a large subway car axle. The various finish fits for this type of axle are, journals 5x9 in., dustgu.. surfaces 6 1/8x2 in., wheel fits 7 7/10 x 6 1/2 in., gear seats 7 1/2 x 6 1/8 in., and axle bearings 6 1/2 x 12 3/4 in. The total length of the axle is 7 ft. 1 in. With the improved lathe equipment this size axle is turned ready for grinding in average of three hours. With the single-tool lathe ordinarily used, the machining operations on an axle of this size would require at least three hours for rough finishing and an additional nine hours for finishing cuts. Previously two different lathes were used, one for rough and the other for finishing, so it was necessary to change the axle from one to the other.
In addition to provisions for multiple tools cutting simultaneously, this type of lathe has a geared headstock providing for six spindle speeds and a geared feed with nine changes. The geared headstock is rugged, so as to withstand the severe strain imposed upon it when several tools are taking heavy cuts. The switch for starting and stopping the machine is on the driving pulley shaft and is operated by the shifter rod placed above the table. In order to obtain rigidity the tool holders are clamped directly to the carriage casting itself, which, in turn, bears directly on the bed of the lathe. This eliminates numerous intervening parts in the supports for the cutting tools and avoids possibility of vibration. The cutting tools do not extend across the bed of the lathe, so that the carriage can be run past the tailstock or back rest without moving the tools from their position. A geared pump built into the head of the lathe provides a continuous flow of cutting compound. The volume of axle work in the Coney Island shops permits the lathes to be kept busy continuously.
Finishing of axles by grinding, which is coming into quite extensive use, has been adopted in the Brooklyn shops. Landis 12x96-in. grinders are used. There is a saving of approximately 25 per cent in the time taken to finish axles as compared with that when they are finished in a lathe. There is also greater accuracy of dimensions and smoothness of finish, so that longer life of bearings results. Where wheels or gears are to be pressed on axles, the grinding finish produces more uniform pressure for the pressing and the grinding finish eliminates irregularities common with filing or rolling, so due to the smoother surface there is a better fit and more surface area in contact between the wheel bore and the axle. This method is also of advantage in producing a better fit of bearing so that the pressure per square inch is reduced. As the pressure employed in grinding is not great, there is little danger of particles of emery becoming embedded in the surface of the axle, and all loose particles are washed away with the heavy flush of water used. Axles without wheels that have surfaces to be trued up go to the grinding machine. Those with wheels mounted go to the gap lathes for truing.
The 200-ton hydraulic axle-straightening press forms an important part of the equipment for the axle section. Every axle without wheels that does not go to the grinder goes to this test machine to determine if it is bent. If so, the straightening becomes an added part of the maintenance procedure.
Besides the machine tools, the axle section contains a large number of portable axle racks. Each will hold seven axles with gears mounted and they are placed at convenient locations so that the jib crane which serves one of the various machines can deposit an axle in one of these racks after it is turned and is waiting to go to the grinding machine. After grinding the same jib crane handles the axle to another rack, or an individual axle can be picked up by an overhead traveling crane and taken to another section as desired.
These axle racks are constructed of angles and channels. The ends form a triangle. Two 12-in. channels form the top portions of the ends. To these, 6-in. angles are riveted to form the support for the ends of the axles. To prevent injuries to the axles the faces of these angles are covered with 1/8-in. copper. Gusset plates strengthen the framework at all corners. The complete rack is 5 ft. wide and 8 ft. long. The bottom framework is constructed of 4-in. angles, with a plate at each corner. These are 6 in. wide and 1/2-in. thick and have holes so that tackle can be fastened to lift the entire rack with load by an overhead traveling crane if desired. As the racks are fitted with wheels they can be moved with their load of axles. The wheels are of 8 in. diameter and have a 4-in. face. The front axle is constructed of a 4-in. I-beam and has a center bearing and circular side bearings so that it can swivel for turning sharp corners and moving about.
Maintenance work on wheels and axles for the entire B.M.T. lines is done at the Coney Island shops. There are three other shops where wheels and axles are removed and installed. A wheel supply flat car makes daily trips to and from the shops. Handling of wheels mounted on axles at the Coney Island shops is facilitated by providing a track into the wheel and axle section so the car can be run inside and loading and unloading done with the overhead traveling crane. The top of the wheel supply flat car has wooden blocking bolted permanently in place to keep wheels from rolling while in transit.
The wheel and axle section also does the finishing work on new armature shafts. A Mitts & Merrill external key seater is used for cutting keyways in shafts.
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| Every axle that does not go to the grinding machine for truing is tested at the 200-ton hydraulic press. If bent, this machine provides a quick means for straightening. | Wheel mounting and check gage. When mounting new or newly turned wheels after one wheel is pressed into position, the stop ^ or S of the mounting gage is placed against the inside of the flange of the wheel pressed in position and the corresponding tread stop C or ) against the tread of the wheel. The second wheel is pressed onto the axle until the opposite tread stop comes in contact with the tread with the corresponding gage point or F in contact with the outside of the flange. For mounting partly worn wheels after one wheel is pressed into position, the stop G or H oi the mounting gage is placed against the side of the flange of the wheel with the corresponding surface I or J resting on the top of the flange. The second wheel is then pressed onto the axle until the opposite stop G or H comes in contact with the inside of the flange of the wheel. In checking wheels when both stops C and D will not rest on the treads of the wheels, they are out of gage. |
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| Layout of machine tools and equipment for the wheel and axle department of the Coney Island shops, Brooklyn-Manhattan Transit Lines. |
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| Boring out a subway wheel. The wheel suspended from the crane on the left is ready to be swung into position. A truck at the right receives wheels after they are bored. The crane at the right handles finished wheels. | A truck load of finished wheels being taken away from the boring mill by an electric crane truck. |
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| A yoke fits between the inside of the wheel and the center frame of the press over the outside of the gear for pressing off wheels from the gear end of the axle. | Pressing a wheel on an axle at the 400-ton hydraulic wheel press. |
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| The yoke used in pressing off wheels at the gear end of the axle and other accessories used in the pressing operation are mounted at the back of the press so as to be swung into position easily by one man. | An average of three pairs of wheels per hour are turned in this wheel lathe. |
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| Rapid Transit Service Requires Careful Checking and Testing of Wheels and Axles. All axles are tested carefully for cracks before being sent out from the wheel and axle department. The axle of the pair of wheels on the stand at the left has just received a bath of kerosene. Axles of mounted wheels on the track at the right have been painted with lime as the second operation of the test. Second view-- Painting the axles of mounted wheels with lime on the test stand. |
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| Third view-- Crack at the end of an axle. The turned sections show the depth and width of the crack at different depths. The bearing fits of axles are protected by wooden strip coverings. These are shown at the right. |
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| Mounted wheels ready for service are placed on racks to keep them on the floor. |
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| Equipment for Axle Work. 1. One of the batteries of three machines used for finishing axles. Two Lo-Swing lathes are shown in the foreground and an axle grinding machine in the rear. Between these are axle racks to receive axles in various stages of completion. |
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| 2. Turning an axle in one of the 8-in. lathes with two carriages having multiple tool posts. 3. The finishing operation of axles is done in a grinding machine. 4. Portable axle racks provide a convenient means for storing axles. |
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| 5. High-power gap wheel turning lathes are used for turning axle bearing fits with wheels mounted. A supply car is shown at the left as it is being loading with wheels to go to other shops of the system. |
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| An external keyseater for armature shafts forms a part of the equipment of the wheel and axle department. |
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| A convenient departmental storage for wheels and axles speeds up production. Material can be brought in on a car and unloaded by the overhead 7-1/2-ton traveling crane. Wheels are loaded on small trucks and taken to the wheel and axle department by electric crane trucks. |
Sources: Electric Railway Journal, McGraw Hill Company, Digitized by Microsoft, Americana Collection, archive.org.
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