General Principles of Design Before proceeding further, your Committee wishes to make clear the use and meaning of certain expressions. The term engine house. is used throughout instead of round house. The terms inner circle and outer circle are used in referring to the engine house of circular shape instead of the ambiguous terms "front" and "rear." Classification There are in general two classes of engines houses which on account of the different purposes they serve require different treatment. 1. Engine houses at points where general shops or other shops for classified repairs are located and where other than running repairs are made in such shops. 2. Engine houses intermediate between such points as are described in (1), where the engines are merely housed, inspected and turned, and where a minimum amount of tool equipment is provided for light running repairs. The assignment of any projected engine house to one of these two general classes is essential before the house is designed. Limiting Factors of Layout The limiting factors in the layout of an engine house of the circular type are: 1. The ultimate number of stalls desired. 2. The spacing of columns on the inner circle. 3. The diameter of the turntable. 4. The practicable distance, center to center, of rails of adjacent tracks at the rim of the turntable to permit the proper clearance between adjacent rails, to secure rigid fastenings and to avoid. the use of frogs. The elimination of frogs, while not essential, is desirable. 5. The arrangement of tracks within and without the house so that as many stalls as practicable will line up with the main lead tracks. Ground Plan Engine houses may be rectangular or circular. Your Committee believes that in general the circular form is preferable and the subject matter of the report refers principally to circular engine houses, but the rectangular houses, as well as circular houses, are shown in the tabulation presented in Exhibit 2. Topographical conditions and restricted property sometimes make this form economical. Number of Stalls The number of stalls varies so with local conditions that it is not possible to establish a general relationship between the number of locomotives turned and the number of stalls that might not be misleading. The quality of water, for instance, has a great influence on the time required to clean boilers, and the method of operation, the switching engines handled, etc., make it desirable that the number of stalls be made an individual study for each engine house, and be determined by the Engineering, Operating and Mechanical Departments working in co-operation. The Committee of the Mechanical Division of the A. R. A. concluded at their meeting on December 15th, 1920, that one turntable was ordinarily sufficient for a 50-stall engine house provided that ample space was provided for in coming and "ready" locomotives to protect the peak demand for power. In locations where many switching engines are handled, it is customary to provide a separate turntable to turn switching engines which do not go into the house. Turntable Very few new engine houses are being constructed with a turntable less than 100 feet long. The general range in length is from 85 to 110 feet. Your Committee feels that the present specification in the Manual is satisfactory, "The turntable should be long enough to balance the engine when the tender is empty." Few turntables, except those serving very small houses, are now without tractors, usually operated by electric power. Length of Engine House Along Center Line of Stall The length of a modern engine house varies from 80 to 132 feet. The length is determined by the class of power to be cared for. In cases where several classes are handled, it is customary to construct sections of different lengths, the number. of stalls of each length being determined by the number of engines of each class to be housed. The conclusion of the Mechanical Division's Committee at the meeting mentioned previously was that the house should be at least twenty (20) feet longer than the longest engine to be housed, in order to allow ten (10) feet for working and trucking space at the outer circle in front of the engine, ten (10) feet at the rear of the engine to provide ample working room with the tender detached and door closed. Your Committee concurs in the conclusion of the Committee of the Mechanical Division. In determining the length of stall, due consideration must be given to future requirements and provision made for extension in length without disturbing the existing structure. Height The height at the inner circle wall should be sufficient to allow for the doors and the necessary lintels over the doors, but greater height than this is not necessary. The height at the outer circle wall should be sufficient to allow the locomotive to pass through the outer wall without damaging the roof structure. It is suggested that in order to provide for future lengthening of stalls the height be such that if the stall length be increased by 25 feet or thereabouts and the existing slope of roof maintained, the necessary clearance below the lintel would still be ample to allow the locomotive to pass beneath without damage to the roof structure. Roof Line The roof line should be such as to: 1. Provide ample natural light where required. The information submitted to the Committee showed a great variety of types of cross-section. These are shown diagrammatically in Exhibit 1. Forty-two railroads are shown as using sixteen (16) different types of cross-section. Of wood frame houses, there are 15 types; of reinforced concrete, 5; of steel, 3; and of those adapted to the use of traveling crane, 3. Frame Details of Design By far the greater number of engine houses are constructed with wood frames because a wood frame building is both economical and durable, except in case of fire. When a wood frame is used, the house should be divided by fire walls into sections of not over ten or twelve stalls each, and the framing should be of the character known as "slow burning" as distinguished from "ordinary" frame construction; that is with brick walls and heavy timber posts and girders and heavy roof sheathing. The desirability of having the engine house fireproof is so evident, and the difference in cost at this time between a fireproof and "slow burning" building is so relatively low, that consideration should, by all means, be given to reinforced concrete or structural steel fireproofed. Reinforced concrete has been subjected to endurance tests now lasting many years and in most cases has proved entirely satisfactory as a framework. In most cases where structural steel, unprotected, is used, special means are provided for the removal of gases, such as in the Pennsylvania System "Type A" house and in the Pittsburgh & Lake Erie standard engine house. Under ordinary conditions, exposed steel is not recommended, and when steel is used, it should be protected by concrete or tile. Floor Information obtained from the questionnaire shows floors in use ranging from creosoted wood blocks to cinders and oiled earth, ranking thus: Where wood block and brick have been reported unsatisfactory, it appears that the trouble has been settlement due to lack of a substantial base, and to the swelling of wood blocks in a few instances. The Committee of the Mechanical Division recommends a permanent floor, preferably wood block or brick on a concrete foundation, around the outer circle, where trucking and the great part of the work are done, extending from the outer wall back possibly two bays to include the front part of the engine. It recommends concrete as satisfactory for the remainder of the floor. The slope of the floor should be sufficient to carry water quickly to the drainage system, about 1⁄2 in. to a foot. Crowning the floor between pits seems to be the ordinary and most satisfactory method of providing floor drainage. In some cases, drainage is provided by depressing the floor between engine pits, collecting the water at catch basins and leading it by drain pipes to the engine pits. Your Committee concurs in the recommendation of the Committee of the Mechanical Division and considers the ideal floor to be of creosoted wood blocks (12 lb. per cu. ft.) laid direct on a six (6) in. concrete base with a bituminous cushion and filler. Such a floor is easy to truck over, easy to work on, does not ship and does not damage engine parts and tools dropped on it. The amount of creosote specified will render the blocks impervious to water. The block ordinarily used for a machine shop floor is not designed to withstand water and is not so suitable for an engine house floor as the block specified. Vitrified brick on a concrete foundation makes a satisfactory and durable floor but one not so easy to truck over or work on. Between the pits, concrete is satisfactory and is less expensive than the other types of floor recommended. Roof There appears to be a considerable difference of opinion as to what constitutes the most satisfactory roof structure. The results of the questionnaire show the following types in use: The reinforced concrete slab ordinarily does not appear to be satisfactory on account of the condensation which collects on its under side. In high altitudes, however, where condensation is slight, it has been satisfactory throughout a number of years' service. The use of a hot blast heating system eliminates much of the condensation which occurs with a direct heating system. In the ordinary range of climates encountered in the United States and Canada, the combination roof of reinforced concrete and hollow tile appears to be the most satisfactory fireproof roof. The hollow tile provides satisfactory insulation and decreases or eliminates the condensation which occurs with a solid slab. Several installations of such roofs, however, which have been in service approximately 8 years have shown a tendency to scale. The bottom surface of both tile and concrete spawls off, leaving the rods exposed. Such instances of deterioration can be overcome by the application of a dense plaster, but this development indicates that although a concrete and hollow tile roof is satisfactory as a fireproof roof, it may not be so durable as a wood roof. On the other hand, the roof on the Baltimore & Ohio engine house at Ivorydale, Ohio, a combination roof of vitrified hollow tile and reinforced concrete, installed in 1905, shows no evidence of deterioration after 16 years' service. The wood roof of slow-burning construction with sheathing two (2) in. or thicker, and heavy purlines spaced at relatively wide intervals, has proved generally to be the most durable and is satisfactory except for its lack of fireproof qualities. The purlines should run radially and not circumferentially so that no pockets will be formed to collected smoke and gases. Gypsum has not yet been subjected to service sufficiently long to determine its durability. Your Committee recommends that where a fireproof roof is desired, a combination reinforced concrete and tile roof be used, while if a nonfireproof roof be used, the sheathing be not less than two (2) in. in thickness and be supported on heavy roof timbers of slow-burning construction. Doors The information obtained from the questionnaire indicates a marked preponderance of opinion in favor of swinging wood doors. Accordion folding doors show promise, and hardware for this type is now being perfected, but these doors have not been subjected to a sufficient test to permit unqualified recommendation. The chief objection to this type of door is the difficulty of making repairs. Any engine house door is liable to damage by locomotives running through it and ease of making repairs is an important characteristic. Rolling lift doors have not been generally satisfactory on account of the liability of the operating mechanism to get out of order and the difficulty of repairing damage inflicted by locomotives. The ranking of various types of doors as indicated by the replies to the questionnaire is as follows: Wood-Swinging Rolling Lift, Wood Slats Steel-Swinging 34 6 3 1 The Committee recommends the wood swinging door as satisfactory and easily kept in repair. When the door is glazed, wire glass should be used. Attention of the Association is called to an arrangement in use on the Central Railroad of New Jersey, and possibly on other railroads, in which the doors are not fastened directly to the inner circle columns but to independent auxiliary columns called "knock-out posts." When the door is hit by a locomotive and forced out, the "knock-out post" fails and allows the door to give way without damage to the main frame work of the engine house. The door opening should be not less than seventeen (17) ft. in height and not less than thirteen (13) ft. in width in the clear. Replies to the questionnaire show an almost equal division of opinion between wood and metal sash. The objection is raised to metal sash that it corrodes quickly and that when damaged by locomotives it can not be easily repaired. The experience of other roads has proved that metal sash will last indefinitely when painted each year and that when subjected to damage it can be repaired more readily than wood sash. Metal sash has the great advantage of providing the greatest ratio of glass area to window opening and simplicity of ventilation by pivoted ventilating sections. Your Committee recommends: 1. For fireproof construction-metal sash. 2. For non-fireproof construction-either metal depending on cost of sash. or wood. |