CEMP-E
TI 850-02
AFMAN 32-1125(I)
1 MARCH 2000
d. Switch Ties.
(1) A turnout is fastened to a special set of ties called a switch tie set. Generally, switch ties increase
in length from the switch point to just past the frog where the turnout ends. From that point, two standard
tracks continue. An exception is at the switch point where the switch stand requires two long ties called
head blocks to accommodate the stand and operating rods. The make-up of switch tie sets will be
determined from table 6-9.
(2) 7-in. x 9-in. hardwood ties will be used for turnouts.
(3) Switch ties will meet the material and treatment specifications for standard track ties covered in
chapter 6, paragraph 14.
e. Switches and Switch Points.
(1) The standard switch for use on military track is the 16 ft, 6-in. switch with graduated risers, as
shown in AREMA Plan 112. The detailed specification for this switch is given in the notes in the upper
right corner of the plan. In most cases, the specification will be for a 112E or 112F (non-insulated hand
throw - rigid braces), or if adjustable braces are desired, specification 112A or 112B - omit insulation
(Note 2(e)), if the switch is not within a signal circuit (as near crossings with warning lights or gates).
Shorter or longer switches may be used, as needed, but switches shorter than 15 ft are not
recommended.
(2) In locations where traffic conditions may cause excessive wear on the tapered ends of the switch
point, the use of alloyed steel (or hardened) switch points is recommended (AREMA Plan 220).
(3) The use of spring switches is not recommended on Army and Air Force track.
f. Switch Clips. Either the adjustable side jaw clip or the adjustable transit clip, as shown at the top of
AREMA Plan 222, are suitable. The slanted row of holes in the clip provides adjustment in switch rod
length ranging from 1/8 in. to 1/2 in., effected by moving the bolt from one hole to another.
g. Rail Braces. The rail braces that support the outside of the stock rails may be either the rigid or
adjustable type. In most cases, rigid braces will suffice, but where movements in both directions through
the turnout may be frequent and under heavy loads, the adjustable braces are recommended.
h. Switch Stands and Lever Latches. Ground throw (low) switch stands are preferred, especially in
terminal areas. However, high stands may be preferred in more remote areas at the ends of passing
sidings or where routes diverge. Many variations of stands are available and most are suitable.
However, any stand selected should have a provision for the throw lever to lock or latch solidly in place.
For switches in more remote areas, a switch point lock and/or lever lock may be desirable.
i. Frogs and Guard Rails.
(1) The solid manganese, self-guarded type frog, as shown in AREMA Plans 641 and 691 (section B-
B), is preferred for the slower speed operations most common at military installations. Self-guarded frogs
simplify turnout construction by not requiring separate guard rails opposite each side of the frog.
6-44
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