Railroad switch heater

Apparatus for heating a railroad rail switch that includes two fixed rails and two switch rails movable laterally to and away from the fixed rails on underlying switch plates and interconnected by switch tie rods, said apparatus comprising:

• an elongate, bendable, high temperature heating cable having a first portion disposed along the outer side of one fixed rail, second portions connected in series with said first portion, extending from the outer side of said one fixed rail toward and back from the other fixed rail under said rails in the region of each of said tie rods, and a third portion connected in series with said first and second portions disposed along the outer side of the other of said fixed rails, each said cable portion comprising an electrical resistance heating wire encased in high temperature resistant electrically insulating material confined inside a thermally conductive deformable metal sheath;
• an elongate, pliable heat insulating mat disposed lengthwise against and along a length of each of said first and third portions of said cable disposed along the outer side of a fixed rail and disposed against portions of the rail web laterally adjacent said first and third cable portions to prevent heat losses by convection or radiation from the cable length, each said mat comprising an elongate mass of high temperature resistant ceramic fiber insulation confined in a flexible sleeve of high temperature resistant wire mesh that prevents fiber of said mass from creeping between the cable and said rail web;
• an elongate, substantially rigid, sheet metal casing member fitted lengthwise over and enclosing each said mat, and bearing along the edges of its side walls against said rail web to confine the mat in place;
• means holding each said channel member tightly in place against the related rail web;
• and
• means for supplying current at high wattage to said wire of each said cable;
• whereby said fixed rails along said cable lengths and consequently said switch plates and said switch rails are heated efficiently by conduction and said tie rods are heated by radiation and convection, yet burn-out of said cables is prevented, during heating of said cables by said current.

Apparatus for heating a railroad rail switch that includes two track rails and two switch rails movable laterally to and away from the track rails on underlying switch plates, each of the track rails being supported laterally at its outer side, along a reach thereof beside a switch rail, by a series of rail braces spaced apart therealong, said apparatus comprising:

• an elongate, bendable, high temperature heating cable disposed along the outer side of each track rail through said reach thereof, each said cable comprising an electrical resistance heating wire encased in high temperature resistant electrically insulating material confined inside a thermally conductive deformable metal sheath, each said cable having a length thereof disposed lengthwise against the web of the related track rail along each region of such rail between adjacent rail braces, and having in the vicinity of each rail brace, between lengths of the cable so disposed, a portion of the cable which is bent upwardly and over the brace;
• an elongate, pliable heat insulating mat disposed lengthwise against and along each said length of said cable and portions of the rail web laterally adjacent thereto to prevent heat losses by convection or radiation from the cable length, each said mat comprising an elongate mass of high temperature resistant ceramic fiber insulation confined in a flexible sleeve of high temperature resistant wire mesh that prevents fiber of said mass from creeping between the cable and said rail web;
• an elongate, substantially rigid, sheet metal casing member of substantially U-shaped cross-section fitted lengthwise over and enclosing each said mat, and bearing along the edges of its side walls against said rail web to confine the mat in place;
• means holding each said channel member tightly in place against the related rail web;
• and
• means for supplying current at high wattage to said wire of each said cable;
• whereby said track rails along said cable lengths and consequently said switch plates and said switch rails are heated efficiently by conduction, yet burn-out of said cables is prevented, during heating of said cables by said current.

A method of preventing obstruction of a railroad rail switch by ice or snow, said switch including a fixed main track rail, a fixed side track rail sloped away from said main rail to form a side track, and main and side switch rails movable laterally to and away from said fixed rails inside the latter on switch plates underlying said rails, said method comprising at times of freezing weather conditions flowing electrical current at high wattage through an electrical resistance wire inside a thermally conductive electrically insulating cable fixed along and next to the outer side of each of said fixed rails at the location of said switch rails, said cable comprising said wire encased in layers of electrically insulating ceramic fibers confined in a heat-resistant metal sheath, obstructing heat flow by radiation and convection from said cable with an elongate, pliable heat insulating mat disposed lengthwise against and along said cable and portions of the web of said fixed rails laterally adjacent thereto, said mat comprising an elongate mass of high temperature resistant ceramic fiber insulation confined in a flexible sleeve that prevents said mass from creeping between said cable and said rails whereby the heat generated in said cable by the current flow passes predominantly into said fixed rails by conduction, and maintaining said switch rails at above freezing temperature by conduction of heat to them through said switch plates.