hr\) complete with a diesel engine driven \(DED\) power source.

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OO-M-2829

Both longitudinal and transverse reinforcing members shall be provided. At the

front of the plate, a front coupling ramp shall be furnished. Ramps that are

not flush with the front crossmember shall include at least four vertical

gussets and shall be provided with holes for water drainage. A 2-inch

(50.8 mm) throat diameter kingpin, conforming to SAE J700, shall be installed

not less than 24 inches (610 mm) nor more than 36 inches (915 mm) from the front

of the semitrailer. The center of the kingpin shall be within 1\8 inch (3 mm)

of the longitudinal centerline of the semitrailer. The swing clearance rearward

from the kingpin to any part of the semitrailer below the upper fifth-wheel

plate shall be not less than 74 inches (1880 mm).

3.11.4 Landing jacks. Landing jacks shall be provided on the semitrailers

for raising, leveling, and supporting each vehicular component unit. The

landing jacks shall be hand or power operated hydraulic units, and shall be

permanently installed on the vehicular component unit. The landing jacks shall

be of such strength, design, and location that coupling and uncoupling the

trailer, with a towing vehicle, will not cause excess stress. Operating jacks

shall be furnished to raise each vehicular component unit into position for

plant operations. Operating jacks shall be of such strength, design, and

location that operation of the plant under load will not cause excess or uneven

stresses. All jacks shall be equipped with square metal mud pads having a

ground bearing area of not less than 100 square inches (645 square centimeters).

The axle, or the forward axle on tandem axles, shall

3.11.5 Running gear.

be in alignment with the longitudinal centerline of the vehicular component unit

so that the two diagonal measurements, from the kingpin to the outer center of

each hub, do not differ in excess of 1/8 inch (3 mm). The rear axle of tandem

axle assemblies shall be in alignment with the front tandem axle so that the

parallel measurements between hub centers on each side do not differ in excess

of 1/8 inch (3 mm). Stub axles or through axles may be furnished. The length

of axle tubes of through axles may be increased during manufacture, providing

the mounting pads are increased at least an equal distance to insure that the

structural rigidity is equal to that of the axles. Axle assembly for the

component units shall be either of the single or tandem axle type, as applicable

for load distribution and weight. All units shall be equipped with suitable

size wheels and tires, in accordance with the recommendations of the TRA, to

withstand the maximum loads, stresses, travel speeds, and with not more than

18,000 pounds (8163 kg) per axle, and shall be compatible with the brake system

in accordance with the loadings.

3.11.6 Brake system. Each wheel component unit shall be equipped with a

service and emergency breakaway, waterproof, all airbrake system, complying with

all applicable DoT Federal Motor Carrier Safety Regulations construction and

performance requirements. The brake system includes service and emergency line

filters, an air reservoir, and an emergency relay valve. All brake system

components shall be located, installed, and protected so that damage from ground

obstructions and debris is prevented and that maximum efficiency and ease of

maintenance is obtained.

3.12 Electrical components.

3.12.1 Diesel engine driven generator set. The DED generator set shall

generate necessary power for the electrical loads specified. The generator set

shall be in accordance with MIL-G-19826. The generator shall be rated