PLS TRAILER (PLST). -726280063

TM 9-2320-364-20-1

1-22. PLS TRAILER (PLST).

Figure 1-28. Palletized Load System Trailer (PLST)

The Palletized Load System Trailer (PLST) (Figure 1-28) is a three axle trailer designed to carry a Flatrack (FR) with

a 33,000 lb (15 metric tons) nominal payload. It can accommodate both full and partial loaded flatracks. Guides

laterally position the FR on the trailer rear stops and these locate the longitudinal position of the FR in relation to the

PLST. These stops prevent the FR from sliding rearward. A pneumatic locking device (1), located between the frame

rails just above the second axle, hooks to engage the lock points and secure the FR to the PLST. An air valve controls

the position of the lock hooks. Springs retain the hooks in the locked position. The PLST has a standard 12 volt

electrical system with 24 volt military adapters (2). Also provided are two intervehicular electrical connecting cables

of sufficient length to reach the towing truck. Two towing eyes (3), at the rear of the PLST permit towing with a

medium duty tow bar. The spare tire carrier is ahead of the second axle in the center of the frame. The spare tire is

held in place with bolts through the wheel bolt pattern. The spare tire and wheel assembly can be raised and secured

in the spare tire carrier by the trailer-provided hand-operated winch. The PLST uses turntable-type steering for

tracking and turning and is equipped with an air braking system. All three axles use 16.5 in. diameter by 7 in. wide

(420 mm by 180 mm) S-cam brakes. The PLST has a dual brake system with separate service and emergency brake

system. The PLST brake system is activated and charged by the truck air supply. The brakes are self-adjusting. Refer

to TM 9-2330-385-14 for Operator's, Unit, Direct Support and General Support Maintenance for the PLS Trailer.

a. Service Brakes. The six service brakes on the PLST are powered by 24/20 inch (61/51 cm) brake chambers.

Six inch automatic slack adjusters are provided with all brake chambers. The service brakes are activated when a

signal from the foot-operated treadle valve or hand operated control valve is sent through a series of relay valves. The

relay valves convert the proportioned service brake signal from the truck into a regulated service brake chamber

pressure.