Wheel Loads

MIL-HDBK-1005/6

See NAVFAC Standard Drawing Nos.

a)

Cast Turntable Frogs.

1294420-22.

See NAVFAC Standard Drawings Nos.

b)

Fabricated Rigid Frogs.

1404038-39.

Fabricated Turntable Frogs .

See NAVFAC Standard Drawings Nos.

c)

1404040-41.

Wheel Loads. See "Wheel Loads for Locomotive and Portal Cranes"

2.2.2.4.

in NAVFAC MIL-HDBK-1025/1, Piers and Wharves. Minimum criteria: 100 kip

vertical, 15 kip lateral, on 3 foot 6 inch centers.

2.2.3

Frogs (Four-Rail Track System).

Design for single flanged wheels.

2.2.3.1

Rigid Frogs.

Material.

Use only cast manganese steel.

2.2.3.2

Wheel Loads. When actual wheel loading is unknown, see "Wheel

2.2.3.3

Loads for Locomotive and Portal Cranes" in NAVFAC MIL-HDBK-1025/1, Piers and

Wharves.

Standard Gage Fittings. Several fitting types commonly used for

2.2.4

standard gage trackwork also have application for crane trackage in three-rail

systems. These include tongue-and-mate switches, guarded split switches, and

standard railroad type frogs.

Tongue and Mate Switches. These fittings are commonly used for

2.2.4.1

railroad turnouts in paved areas. In three-rail systems where standard gage

and wide gage share a common rail, and the standard gage diverges from a wide

gage, a mate may be used. The mate allows the single-flanged wheels to divert

from the crane rail without interfering with crane double-flanged wheels.

Guarded Split Switch. In cases where a tongue-and-mate switch can

2.2.4.2

be used in a three-rail system, a guarded split switch is also applicable as

an alternative. A guarded split switchpoint on the crane rail allows passage

of crane wheels along the stock crane rail when in the open position. When

closed, the switchpoint provides a continuous rail head for single-flanged

wheels diverging from the crane rail. Where a standard gage turnout requires

single flange wheels to cross the crane rail at the switchpoint, a

double-tongue switch must be used.

Railroad Type Frogs. These are not for use with crane rails, but

2.2.4.3

may be used in three-rail systems where both intersecting rails are used by

single-flanged wheels. Self-guarded frogs in paved areas are not desirable;

guard rails are therefore required.

2.2.5

Manual Calculations (Two-Rail Switch).

Flangeway Spacing Computation. For each integer X, sum the

2.2.5.1

corresponding circular and linear offsets as given below. Subtract the

railhead width to obtain the flangeway spacing. Switch length and the end

spacing -b can be varied as required. See Figure 3.

2.2.5.2

Circle Offset Computation.

Variable Definitions:

25