1. Manganese Steel Castings: Most existing crane
track fittings are of this type, which has a
superior ability to withstand wear. These castings
are, however, costly when custom-manufactured, and
require long lead time to order.
2. Fabricated (Build-up) Fittings: Fabricated
crane track switches and frogs are alternatives to
the conventional cast fittings. They consist of
stock rails and a number of steel plates bolted
and/or welded together into the required
configuration. Due to the use of standard
components, many machine shops are capable of
producing fabricated fittings, thus reducing cost
and lead time. Fabricated fittings are, however,
heavier and less wear-resistant than cast fittings.
Military standards as listed in this guide
specification are available for both types of
fittings and paragraphs are provided for both types.
Delete paragraphs referring to inapplicable types of
fittings. For further information on use of cast
and fabricated fittings contact:
Commander
Atlantic Division
Naval Facilities Engineering Command
Code 15C2
Bldg. N-26, Room 234
Norfolk, VA 23511-6287
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Provide configuration and geometry of fittings as indicated and as
specified herein. Substitutions will not be accepted. Fittings include
[switches] [and] [frogs] for use with crane wheels indicated.
2.2.1
Four-Rail Portal Crane Track Systems
**************************************************************************
NOTE: There are two types of portal crane trackage
systems in use in the Naval Shore Establishment:
1. Four-Rail System: This system consists of two
standard gage (railroad) tracks. The cranes for
this system are equipped with single-flanged wheels.
Switches and frogs are of the standard railroad
type except for some small frog angles, where
turntable frogs may be required. For details of
two- and four-rail system applications, see
MIL-HDBK-1005/6. This guide specification may be
used for either two-rail or four-rail crane track
systems by deletion of inapplicable paragraphs
describing the use of specific types of switches and
frogs. For four-rail systems, additional references
based on Section 05650, "Railroad Track and
Accessories" for Standard Gage Railroad Track may be
used.
2.
Two-Rail System:
The cranes for this system are
SECTION 14606N
Page 14
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