CEMP-E
TI 850-02
AFMAN 32-1125(I)
1 MARCH 2000
(2) Rail bound manganese (RBM) frogs, as shown in AREMA Plan 600, may be used on heavy traffic
lines where the traffic is approximately equal on both sides of the frog. This type of frog is most desirable
for long turnouts (size 15 or above) since manganese steel is especially suited to the thin long points and
requires comparatively little maintenance.
(3) Bolted rigid frogs, as shown in AREMA Plan 320, can be used at any location on military
installations. However, when new frogs are required, the two choices above are preferred.
(4) Spring rail frogs will not be used on Army and Air Force installations.
(5) Frogs are secured to ties with a set of hook plates, as shown in AREMA Plan 241.
(6) When not using self guarded frogs, guard rails will be specified to match the frog size, as listed in
Note 2A of AREMA Plan 502. Guard rails of the type in AREMA Plans 504 or 510 may be used.
j. Stock Rails and Closure Rails.
(1) Enough rail to make up the straight and curved stock rails and closure rails must be supplied, as
indicated in AREMA Plan 910 or 911. This amount will approximately equal twice the actual lead
(Column 4) plus the closure distances (Columns 5 and 6).
(2) All rail within the limits of a new or secondhand turnout will be of the same weight and section,
and should match the rails on the main and diverging tracks. Compromise joints are not permitted within
the limits of a turnout.
(3) Where new switch points are specified with relay closure rail, a check must be made to assure
that the top and gage side of the points and closure rails match at the heel joint.
(4) When turnouts will be rebuilt, and both new and relay rail will be available on the project, it is
recommended that new rail be used to reconstruct the turnouts; this will avoid the potential problem of rail
contour mismatch at the switch heel joints.
k. Layout Data and Dimensions.
(1) In most cases, designers will use the dimensions and layout data for standard turnouts shown in
AREMA Plans 910 and 911, with turnout size selected from table 6-12 and component options as
discussed above. Turnouts may be laid out as left-hand, right-hand, or equilateral, as shown in figure 6-
25.
(2) On occasions when nonstandard layout is required, or where different point lengths are used,
turnout layout may be determined from figure 6-28 and equations 6-12 through 6-15.
6-45
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