| 摘要 |
A railroad switch heating system comprises lengths of a pliable insulated electrical resistance heating cable disposed against and along the outer sides of the fixed rails of the switch, with portions of these cable lengths between rail braces overlaid by thermally insulating mats and against the adjacent rail web surfaces, and supplemental heating to prevent ice formation in the crib space of, and excessive heat losses through, a rod interconnecting the displaceable rails near the switch points is provided by a crib heating unit having a sinuously bent length of the cable arranged over a pan-like support of sheet material that fits between and along the ties bordering the crib space beneath the rod therein. The pan-like support becomes heated by conduction and heats substantially the entire crib space by radiation and convection. Where the switch points move on a gauge plate extending between them on a track tie, the fixed rail heating is further supplemented by heating units that include rigid plate members which straddle and hold sinuously bent lengths of the cable against areas of the gauge plate near the switch points, with heat insulation. Each cable length has the ends of its heating wire fitted with connectors joining it with insulated conductors in a series heating circuit to be activated when weather conditions might cause freezing at the switch. Lengths of bendable metal tubing enclosing the cable lengths and special water-tight connectors render the heating system water-tight, thus enhancing its safety and reliability.
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