Railroads provide a major mode of transportation around the world. Today, even with competition from road and airborne transport, rail remains an important means of land-based movement of bulk quantities of goods and materials. Railroad operations are carried out in an enormously wide variety of terrains and climates, from Arctic permafrost to equatorial jungle, from rainforest to desert. The roadbed of partly crushed stone (ballast) and track consisting of steel rails and ties of wood, concrete or steel are common to all railroads. Ties and ballast maintain the position of the rails.

The source of power used in railroad operations worldwide (steam, diesel-electric and current electricity) spans the history of development of this mode of transportation.

Administration and Train Operations

Administration and train operations create the public profile of the railroad industry. They ensure that goods move from origin to destination. Administration includes office personnel involved in business and technical functions and management. Train operations include dispatchers, rail traffic control, signal maintainers, train crews and yard workers.

Dispatchers ensure that a crew is available at the appropriate point and time. Railroads operate 24 hours per day, 7 days per week throughout the year. Rail traffic control personnel coordinate train movements. Rail traffic control is responsible for assigning track to trains in the appropriate sequence and time. This function is complicated by single sets of track that must be shared by trains moving in both directions. Since only one train can occupy a particular section of track at any time, rail traffic control must assign occupancy of the main line and sidings, in a manner that assures safety and minimizes delay.

Signals provide visual cues to train operators, as well as to drivers of road vehicles at level train crossings. For train operators, signals must provide unambiguous messages about the status of the track ahead. Signals today are used as an adjunct to rail traffic control, the latter being conducted by radio on channels received by all operating units. Signal maintainers must ensure operation of these units at all times, which can sometimes involve working alone in remote areas in all weather at any time, day or night.

Yard workers’ duties include ensuring that the rolling stock is prepared to receive cargo, which is an increasingly important function in this era of quality management. Tri-level automobile transporter cars, for example, must be cleaned prior to use and readied to accept vehicles by moving chocks to appropriate positions. The distance between levels in these cars is too short for the average male to stand upright, so that work is done in a hunched over position. Similarly, the handholds on some cars force yard workers to assume an awkward posture during shunting operations.

For long runs, a train crew operates the train between designated transfer points. A replacement crew takes over at the transfer point and continues the journey. The first crew must wait at the transfer point for another train to make the return trip. The combined trips and the wait for the return train can consume many hours.

A train trip on single track can be very fragmented, in part because of problems in scheduling, track work and the breakdown of equipment. Occasionally a crew returns home in the cab of a trailing locomotive, in the caboose (where still in use) or even by taxi or bus.

The train crew’s duties may include dropping off some cars or picking up additional ones en route. This could occur at any hour of the day or night under any imaginable weather conditions. The assembly and disassembly of trains are the sole duties of some train crews in yards.

On occasion there is a failure of one of the knuckles that couple cars together or a break in a hose that carries braking system air between cars. This necessitates investigative work by one of the train crew and repair or replacement of the defective part. The spare knuckle (about 30 kg) must be carried along the roadbed to the repair point, and the original removed and replaced. Work between cars must reflect careful planning and preparation to ensure that the train does not move during the procedure.

In mountainous areas, breakdown may occur in a tunnel. The locomotive must maintain power above idle under these conditions in order to keep the braking functional and to prevent train runaway. Running the engine in a tunnel could cause the tunnel to fill with exhaust gases (nitrogen dioxide, nitric oxide, carbon monoxide and sulphur dioxide).

Table 1 summarizes potential hazardous conditions associated with administration and train operations.

Table 1. Hazardous conditions associated with administration and train operations.

Maintenance of Rolling Stock and Track Equipment

Rolling stock includes locomotives and railcars. Track equipment is specialized equipment used for track patrol and maintenance, construction and rehabilitation. Depending on the size of the railroad, maintenance can range from onsite (small-scale repairs) to complete stripdown and rebuilding. Rolling stock must not fail in operation, since failure carries serious adverse safety, environmental and business consequences. If a car carries a hazardous commodity, the consequences that can arise from failure to find and repair a mechanical defect can be enormous.

Larger rail operations have running shops and centralized stripdown and rebuild facilities. Rolling stock is inspected and prepared for the trip at running shops. Minor repair is performed on both cars and locomotives.

Railcars are rigid structures that have pivot points near each end. The pivot point accepts a vertical pin located in the truck (the wheels and their support structure). The body of the car is lifted from the truck for repairs. Minor repair can involve the body of the car or attachments or brakes or other parts of the truck. Wheels may require machining on a lathe to remove flat spots.

Major repair could include removal and replacement of damaged or corroded metal sheeting or frame and abrasive blasting and repainting. It could also include removal and replacement of wooden flooring. Trucks, including wheel-axle sets and bearings, may require disassembly and rebuilding. Rehabilitation of truck castings involves build-up welding and grinding. Rebuilt wheel-axle sets require machining to true the assembly.

Locomotives are cleaned and inspected prior to each trip. The locomotive may also require mechanical service. Minor repairs include oil changes, work on brakes and servicing of the diesel engine. Removal of a truck for wheel truing or evening may also be needed. Operation of the engine may be required in order to position the locomotive inside the service building or to remove it from the building. Prior to re-entry into service the locomotive could require a load test, during which the engine is operated at full throttle. Mechanics work in close proximity to the engine during this procedure.

Major servicing could involve complete stripdown of the locomotive. The diesel engine and engine compartment, compressor, generator and traction motors require thorough degreasing and cleaning owing to heavy service and contact of fuel and lubricants with hot surfaces. Individual components may then be stripped and rebuilt.

Traction motor casings may require build-up welding. Armatures and rotors may need machining in order to remove old insulation, then be repaired and impregnated with a solution of varnish.

Track maintenance equipment includes trucks and other equipment that can operate on road and rail, as well as specialized equipment that operates only on rail. The work may include highly specialized units, such as track inspection units or rail-grinding machines, which may be “one of a kind”, even in large railroad companies. Track maintenance equipment may be serviced in garage settings or in field locations. The engines in this equipment may produce considerable exhaust emissions due to long periods between service and lack of familiarity of mechanics. This can have major pollution consequences during operation in confined spaces, such as tunnels and sheds and enclosing formations.

Table 2 summarizes potential hazardous conditions associated with maintenance of rolling stock and track equipment as well as transportation accidents.

Table 2. Hazardous conditions associated with maintenance and transportation accidents.

Maintenance of Track and Right of Way

Maintenance of track and right of way primarily involves work in the outdoor environment in conditions associated with the outdoors: sun, rain, snow, wind, cold air, hot air, blowing sand, biting and stinging insects, aggressive animals, snakes and poisonous plants.

Track and right-of-way maintenance can include track patrol, as well as the maintenance, rehabilitation and replacement of buildings and structures, track and bridges, or service functions, such as snowplowing and herbicide application, and may involve local operating units or large, specialized work gangs that deal with replacement of rails, ballast or ties. Equipment is available to almost completely mechanize each of these activities. Small-scale work, however, could involve small, powered equipment units or even be a completely manual activity.

In order to carry out maintenance of operating lines, a block of time must be available during which the work can occur. The block could become available at any time of day or night, depending on train scheduling, especially on a single-track main line. Thus, time pressure is a main consideration during this work, since the line must be returned to service at the end of the assigned block of time. Equipment must proceed to the site, the work must be completed, and the track vacated within the set period.

Ballast replacement and tie and rail replacement are complex tasks. Ballast replacement first involves removal of contaminated or deteriorated material in order to expose the track. A sled, a plow-like unit that is pulled by a locomotive, or an undercutter performs this task. The undercutter uses a continuous toothed chain to pull ballast to the side. Other equipment is used to remove and replace rail spikes or tie clips, tie plates (the metal plate on which the rail sits on the tie) and ties. Continuous rail is akin to a noodle of wet spaghetti that can flex and whip and that is easily moved vertically and laterally. Ballast is used to stabilize the rail. The ballast train delivers new ballast and pushes it into position. Labourers walk along with the train and systematically open chutes located at the bottom of the cars in order to enable ballast to flow.

After the ballast is dropped, a tamper uses hydraulic fingers to pack the ballast around and under the ties and lifts the track. A spud liner drives a metal spike into the roadbed as an anchor and moves the track into the desired position. The ballast regulator grades the ballast to establish the final contours of the roadbed and sweeps clean the surface of the ties and rails. Considerable dust is generated during ballast dumping, regulating and sweeping.

There are a variety of settings in which track work can take place—open areas, semi-enclosed areas such as cuts, and hill and cliff faces and confined spaces, such as tunnels and sheds. These have a profound influence on working conditions. Enclosed spaces, for example, will confine and concentrate exhaust emissions, ballast dust, dust from grinding, fumes from thermite welding, noise and other hazardous agents and conditions. (Thermite welding uses powdered aluminium and iron oxide. Upon ignition the aluminium burns intensely and converts the iron oxide to molten iron. The molten iron flows into the gap between the rails, welding them together end to end.)

Switching structures are associated with track. The switch contains moveable, tapered rails (points) and a wheel guide (frog). Both are manufactured from specially hardened steel containing a high level of manganese and chromium. The frog is an assembled structure containing several pieces of specially bent rail. The self-locking nuts which are used to bolt together these and other track structures may be cadmium-plated. Frogs are built up by welding and are ground during refurbishing, which can occur onsite or in shop facilities.

Bridge repainting is also an important part of right-of-way maintenance. Bridges often are situated in remote locations; this can considerably complicate provision of personal hygiene facilities which are needed to prevent contamination of individuals and the environment.

Table 3 summarizes the hazards of track and right-of-way maintenance.

Transportation Accidents

Possibly the greatest single concern in rail operations is the transportation accident. The large quantities of material that could be involved could cause serious problems of exposure of personnel and the environment. No amount of preparation for a worst-case accident is ever enough. Therefore, minimizing risk and the consequences of an accident are imperative. Transportation accidents occur for a variety of reasons: collisions at level crossings, obstruction of the track, failure of equipment and operator error.

The potential for such accidents can be minimized through conscientious and ongoing inspection and maintenance of track and right-of-way and equipment. The impact of a transportation accident involving a train carrying mixed cargo can be minimized through strategic positioning of cars that carry incompatible freight. Such strategic positioning, however, is not possible for a train hauling a single commodity. Commodities of particular concern include: pulverized coal, sulphur, liquefied petroleum (fuel) gases, heavy metal concentrates, solvents and process chemicals.

All of the groups in a rail organization are involved in transportation accidents. Rehabilitation activities can literally involve all groups working simultaneously at the same location on the site. Thus, coordination of these activities is extremely important, so that the actions of one group do not interfere with those of another.

Hazardous commodities generally remain contained during such accidents because of the attention given to crashproofing in the design of shipping containers and bulk rail cars. During an accident, the contents are removed from the damaged car by emergency response crews that represent the shipper. Equipment maintainers repair the damage to the extent possible and put the car back on the track, if possible. However, the track under the derailed car may have been destroyed. If so, repair or replacement of track occurs next, using prefabricated sections and techniques similar to those described above.

In some situations, loss of containment occurs and the contents of the car or shipping container spill onto the ground. If substances are shipped in quantities sufficient to require placarding because of transportation laws, they are readily identifiable on shipping manifests. However, highly hazardous substances that are shipped in smaller quantities than mandated for listing in a shipping manifest can escape identification and characterization for a considerable period. Containment at the site and collection of the spilled material are the responsibility of the shipper.

Railway personnel can be exposed to materials that remain in snow, soil or vegetation during rehabilitation efforts. The severity of exposure depends on the properties and quantity of the substance, the geometry of the site and weather conditions. The situation could also pose fire, explosion, reactivity and toxic hazards to humans, animals and the surrounding environment.

At some point following the accident, the site must be cleared so that the track can be put back into service. Transfer of cargo and repair of equipment and track may still be required. These activities could be dramatically complicated by the loss of containment and the presence of spilled material. Any action taken to address this type of situation requires considerable prior planning that includes input from specialized knowledgeable professionals.

Hazards and Precautions

Table 1,  table 2 and table 3 summarize the hazardous conditions associated with the various groups of workers involved in railroad operations. Table 4 summarizes the types of precautions used to control these hazardous conditions.

Table 3. Hazardous conditions associated with maintenance on track and right of way.

Table 4. Railway industry approached to controlling hazardous conditions.

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