1 MARCH 2000
(2) Recommended relay rail sections are: 100ARA-B, 112RE, 115RE, 130RE, 132RE, 133RE, and
(3) Relay rail should be selected to limit the number of different rail weights and sections within the
track network. For a given weight, the section and joint drilling pattern (bolt-hole size and spacing) should
also be consistent.
(4) Due to the varying market for relay rail it may be beneficial to allow the contractor an option to
provide an acceptable rail section. Selection should be limited to those sections that are sufficiently
plentiful to supply future maintenance purchase requirements: rail, joint bars, frogs and other turnout
e. Lightweight Rail.
(1) Lightweight rail weighs less than 90 lb per yd. These weights are no longer manufactured and
are only available as secondhand.
(2) For main running tracks, rail weights less than 90 lb per yd will not be used. Rail weighing 75 lb
per yd to 85 lb per yd may be adequate for terminals and auxiliary tracks with light use, depending upon
support conditions. A structural evaluation is necessary to determine the adequacy of these rail weights.
Rail not adequate to support the desired wheel loads should be replaced.
f. Continuous Welded Rail (CWR).
(1) Continuous welded rail (CWR) is strings of standard rail welded together either in a rail plant or by
field welding after installation. CWR is commonly used on commercial railroads and is beneficial in
reducing maintenance costs due to rail joints.
(2) CWR is not recommended for general use on military track because it: (1) requires a larger ballast
section to provide sufficient track restraint, (2) needs more rail anchors to restrain longitudinal rail
expansion, (3) is more subject to buckling in hotter weather and pull-aparts during colder weather, and (4)
has a higher initial installation cost. If conveniently available, short strings (less than 200 ft) may be
appropriate for wide road crossings or track in paved areas. CWR may have good application on certain
lines that form a long connection to the serving commercial carrier.
g. Field Welds.
(1) It is recommended that rail through road crossings and for 20 ft on either side of crossings be
welded to eliminate joints in these areas. Likewise, field welding should be considered for rail placed in
confined loading areas, adjacent to warehouse loading docks, and in other areas where maintenance
access to rail joints would be difficult.
(2) Rail welding may only be accomplished with special thermite welding kits designed for this
purpose and by people with the necessary training and experience in welding rail. Where many welds
are to be done, some specialized contractors have truck-mounted electric welding units designed for this