any machine that repairs and maintains existing railroad track and constructs new track. Most track machines function on rails, but others have caterpillar treads or run on either rails or pneumatic wheels.
Track machines fulfill all types of track operations. The roadbed is repaired and maintained by grading machines and track-maintenance machines and is ballasted by electroballasting equipment, tractor-mounted ballast regulators, and track jacks. Machines for ballasting raise and shift the rails and ties, feed the ballast to the roadbed, and deposit the ballast in a layer of specified thickness. Ballast-cleaning machines remove dirt and debris from ballast.
On railroad lines in use, tracklayers on wheels lay and move rails and ties during repair and during the construction of track. Tractor-driven tracklayers are used when a new railroad is built. If all rails are to be replaced, a rail-layer is used. Track units are assembled and dismantled with track-assembly and track-dismantling machines.
Tamping machines are used to consolidate ballast beneath the ties and to align the track. When rails and ties have been removed, these machines are of the walking type. Aligning, tamping, and finishing machines perform operations that level the track and align it transversely, lengthwise, and in plan to tamp the ballast section, and round the ballast slopes.
Workers are usually brought to the working site in handcars. Both handcars and hopper cars are utilized to transport materials. The condition of tracks is inspected with track indicators that determine the position of tracks and with detector cars or trolleys that locate flaws in the rails. Other track machines include rail-welding machines, which weld long sections of rail that are laid to form jointless track, and machines that grind joints and straighten rails. Snowplows and snow sweepers remove snow from the tracks, pneumatic snowblowers blow snow away from the switches, and gas or electric heaters melt snow accumulated on switches. Other track machines include cranes, bulldozers, and belt conveyors.
Most track machines that operate on tracks closed to train traffic are of a heavy-duty type and cannot be removed from the tracks. For small-scale work, lighter machines are used. Such machines are operated during the intervals between the passage of trains and can be removed to one side of the tracks when a train approaches. Light machines include track jacks, motorized handcars, track indicators, and flaw-detecting trolleys and such mechanized track implements as rail-cutting, rail-drilling, and rail-grinding machines and bolt-tightening and spiking devices.
Rail systems outside of the USSR that have a low traffic density use track machines that are light and mobile but less efficient than Soviet machines. The high density of freight traffic carried by the railroads of the USSR necessitates a minimal shutdown period when track is under repair. For this reason, track machines manufactured in the USSR are highly efficient.
Future development of track machines will include the total mechanization of track work, increased dependability, lower costs and consumption of power and metal, and standardization of units and parts. Important trends are the adoption of monitoring and automated systems and the development of new and the improvement of existing devices for monitoring tracks. Particular attention is being devoted to providing personnel with means of protection against dust, noise, and vibration. The chief aim in designing mechanized devices and light track machines is reduction of bulk through the use of lightweight materials and better design.
REFERENCEMashiny i mekhanizmy dlia putevogo khoziaistva. Moscow, 1970.
S. A. SOLOMONOV