TM-55-2350-215-10-15

TM 55-2350-215-10-15

practical.

Civil highway permit officials should be

consulted to determine specific permit requirements for

the state or country in which the movement is planned.

Bridge Limitations

The high tandem axleloads

and suspension characteristics may overstress typical

bridge structures in the United States.

Most States will

permit tandem axleloads of up to 50,000 pounds under

special conditions.

Accordingly, all highway movements

of the M60-series tank on the HET system may be

refused or required to have a "certification of essentiality

to national defense." The certification is issued to the

appropriate State highway department by the major

command making the move and is required prior to

movement.

Loaded Characteristics

Characteristics of the

loaded system are shown in individual axle weights in

figure 5-1.

The HET transport system's tandem axles,

that is, the two adjacent axles pivoting at a single

suspension point, are over the 50,000-pound tandem-

axleload limit recommended by AASHTO.

When the

M60-series tank is positioned on the M747 semitrailer so

that the load is equally distributed to all axles, the

tandem axleload limit is exceeded.

The rear two axles

of the M746 semitrailer are retractable pusher axles.

When extended, they can be adjusted to push against

the surface to distribute the load to all four axles of the

semitrailer.

The M746 truck tractor has two sets of

tandem axles.

The M911 truck tractor has one set of

driving tandem axles, a single steering axle, and a

single pusher axle just forward of the tandem axles.

The pusher axle may be extended to distribute the load

when the fifth-wheel load increases the tandem axleload

to greater than acceptable limits.

Placement of the

M60A3 tank's center of balance 243 inches from the

kingpin of the M747 semitrailer, with the semitrailer

pusher axles properly extended (when towed by the

M746 truck tractor), will achieve the individual axleloads

shown in figure 5-1.

Placement of the M60A3 tank's

center of balance 237 inches from the kingpin of the

M747 semitrailer, with the tractor pusher axle and the

semitrailer pusher axles properly extended (when towed

by the M911 truck tractor), will achieve individual

axleloads shown in figure 5-1.

5-2

TANK, COMBAT, FULL-TRACKED, M60-SERIES

TRANSPORTABILITY GUIDANCE