METHODS of CLEANING STONE BALLAST Report of Committee
Total Page：16
File Type：pdf, Size：1020Kb
METHODS OF CLEANING STONE BALLAST Report of Committee L. J. Drumeller division engineer, C. & 0., Hinton, W. Va. Probably one of the most important problems that has confronted maintenance officers during the last five years has been that of keeping the ballast section cleaned, particularly in stone-ballasted territories. This condition was largely brought about by a curtailed labor allowance which made it necessary to direct practically all available funds to line and surface, tie renewals, and such other maintenance work as was necessary for the safe operation of trains. These conditions resulted in the usual ballast cleaning and renewal cycle being prolonged two and, in some cases, three fold. Clean, crushed stone ballast is recognized as the most satisfactory ballast in dense-traffic territory, and one of the underlying requirements of a well maintained railroad is clean, live ballast. Those railroads which were able to maintain such a condition through the past few years are fortunate. Before discussing the various methods of cleaning stone ballast, it may be well to outline briefly some of the major conditions that cause ballast to become foul. They include the following: 1. Inadequate surface and subsurface drainage. 2. Battered rail ends, causing joints to vibrate excessively under wheel loads. 3. Burned rail, due to slipping drivers, bringing about the same condition as in Item 2. 4. Front-end sparks from locomotives operating on heavy grades. 5. Commodities such as coal, coke, etc., in territories close to the points of loading. 6. Leakage through floors and hopper-bottoms of cars. 7. The elements, causing the deposit of wind-blown dirt, etc., on ballast. 8. The kind and size of the ballast. 9. Sanding rails on heavy grades and at starting points, such as stations, signal locations and water stations. 10. Continuous switching on main lines where no switching leads are provided. 11. Fine stone screenings or shale from crumbled limestone, which is likely to be loaded at the quarries with the crushed stone if not properly inspected. 12. Narrow side ditches where cuts are too narrow to permit proper ditches, thereby retarding drainage. Stone ballast is used chiefly on the eastern railroads and from these railroads it is learned that the interval between ballast cleanings vanes from two to eight years, depending chiefly upon traffic conditions and the location. As pointed out by a maintenance officer of one of the country's leading railroads, the cleaning of stone ballast improves the drainage by removing the dirt and opening up the voids between the stones. When such a condition of the ballast is maintained continuously it results in the following: 1. Drains surface water away from the track. 2. Reduces the labor of maintaining line and surface. 3. Increases the life of rail, ties, fastenings, etc. 4. Improves the general appearance of the right-of-way and, to a large extent, keeps down the dust. In the past 12 years various machines have been developed for the cleaning of stone ballast, but prior to that time practically all ballast was cleaned by hand. Methods of Cleaning Ballast by Hand Hand cleaning of ballast is done with both forks and screens. In cleaning ballast with forks, the ballast is dug out with picks and shovels and thrown upon the roadbed shoulder. If wet or damp, it is first allowed to dry and is then shaken clean with the aid of forks and cast back into the track. Another method of cleaning ballast in the cribs with forks is to dig out one crib completely and fork clean ballast back into it from the adjacent crib, this performance being repeated throughout the section of the track being cleaned. In applying this method, the margin ballast is usually forked up in between the rails and behind the crib-cleaning, allowing the waste to fall upon the roadbed shoulder. The roadbed is then cut down to proper depth below the ties to provide adequate drainage and the ballast is replaced. When cleaning the intertrack space with forks, a common method is to dig a hole to the proper depth below the ties, and then fork the clean ballast progressively to the rear, removing the dirt which falls through the ballast forks with a shovel at suitable intervals by casting it over the side of the embankment. Portable Screens Were Introduced With the increasing need for maintaining clean stone ballast, certain ballast screens were introduced. Possibly the one most commonly used is about three feet wide and six feet long, which is placed in position for use with one end resting on the ground and the other on standards that are adjusted to provide any desired slope. The best results are usually obtained by placing the screen on a 45-deg. angle. Ballast is shoveled upon the screen near the top and allowed to roll down, the waste passing through the screen into a metal tray beneath and the clean ballast rolling back on the ground. When full, the metal trays are removed and the waste is thrown over the side of the embankment or along the roadbed shoulder. With both the hand and screen methods of cleaning ballast, it is advisable to assign each man a designated portion of track over which to work, say one rail length, thus not only spacing the force to provide closer supervision but also setting up competition among members of the gang. Under the very best conditions, the cleaning of stone ballast with either forks or screens is expensive, and in some cases it is considered more economical to throw away the old ballast to a certain depth below the ties and add fresh ballast than attempt to clean the old ballast. This depends, of course, on how old and dirty the ballast is and over what distance it is necessary to haul the new ballast. The cost of cleaning stone ballast by hand, with either forks or screens, varies widely, depending on the condition of the ballast, traffic density and wages. In view of the recognized importance of keeping stone ballast clean and the almost prohibitive cost of performing this work by hand, machines of various types have been developed and placed in service on various railroads throughout the country. These are discussed below. The MacWilliams Mole Ballast Cleaner Ballast moles have been in operation since the summer of 1926, when eight of them were built and delivered to two railroads. Since that time, 203 moles have been put in service on 14 different railroads. These machines are powered by gasoline engines and are designed to work both in the margin ballast and in the intertrack space. They will clean to depths ranging from 14 in. to 24 in. below the tops of the ties, depending on the requirements of the railroad on which they are employed. Moles working in the intertrack space are provided with two lines of portable racks in about 10-ft. sections, one line being laid on the inner tie ends of each track. This rack serves to keep the machine in a true line. As the mole progresses, the racks are taken up from the rear and placed ahead. The shoulder or margin moles are likewise equipped except that they have only one line of portable rack, placed on the outside tie ends, and are supported on the opposite side by a large wheel which operates along the roadbed shoulder. The margin moles can also be worked in the intertrack space by removing the large wheel. When these machines are operating, two digging arms located on the front end feed the ballast to a conveyor belt which carries it back and drops it on a shaker screen or agitator. The dirt drops through the screens on to a side conveyor belt which deposits it along the roadbed shoulder, whence it is later thrown over the side of the fill or hauled out of the cut, depending upon local conditions. The clean ballast, after passing over the screen, falls back into the space from which it was dug. When normally set, moles clear passing trains, but their operation must of necessity be discontinued while trains are passing. These machines are usually operated in batteries of two - one in the intertrack space and the other in the margin, but it is reported that in four-track territory they are sometimes worked in batteries of three, one machine being operated in the intertrack space. The advantage of working more than one machine with a gang lies in the reduction in overhead expense, necessitating the use of only one foreman and a cook. It is also reported that in some instances the machines have been worked two eight-hour shifts per day. Figures available during the last five years indicate that moles average from 700 to 1195 ft. per eight-hour day in the intertrack space and from 850 to 1200 ft. in the margin., the performance depending on the depth cleaned, on whether or not the crib ballast is dug out and thrown into the center and on the margin ahead of the mole, in which case it is necessary to work it in low gear, resulting in slower speed but maintaining about the same volume of ballast cleaned. When being moved over highway crossings or other obstructions, the moles are lifted out of the intertrack space to a sufficient height to clear the obstructions by means of chain hoists supported from A-frames, which are propelled along the running rails of both tracks far enough to clear the obstruction. Figures available on various railroads show that moles will clean the intertrack space at a cost of from 4 cents to 6 cents per lineal foot of track and about 3 cents per lineal foot along the margin, this cost being based on the cleaning of 20 miles or more per season and includes labor, fuel and supplies, running repairs, depreciation at 12-1/2 per cent and annual general repairs.