TM 55-2200-001-12
Change 3
Sec. 6
MAJOR CALIBRE GUN BARRELS
GENERAL INSTRUCTIONS
Cars used for transporting gun barrels must conform to the requirements of General Rule 21.
As shipments will in most cases require a minimum of two cars, the cars should be equipped as follows:
Each car should be fitted with a pivoted bolster In the center of the car. The bolster on one car should have a
Fixed Center Plate, while the bolster on the other car should have a Movable Center Plate, see Fig. 5. The bolsters, if
the property of a railroad, must accompany the cars in both the loaded and empty movement of the cars. Each end of
each bolster should be equipped with permanent turnbuckle.
When cars move empty the bolsters should be securely fastened with the turnbuckle hooked to side stake pocket
and made taut-on both sides of car. When cars are loaded, these turnbuckles must be unhooked and slid into the ends
of the bolsters.
The shippers must provide themselves with blocks, securements and fastenings as shown In Figs. 84, 85 and 86
for shipments of 16 in. gun barrels.
For the shipment of other size gun barrels the same method of securement must be used and the details of same
submitted to the originating carrier for approval before shipments are made.
Unless other arrangements are made locally, detail blocks securements and fastenings furnished by shipper, which
are not a part of the equipment attached to the car or cars, should be returned to the point of origin, under revenue
billing, after the gun barrel has been unloaded; on cars if they are to return to the point of origin, and In other equipment
if the cars do not return to the point of origin. Method of securing gun barrel equipment after gun barrel has been
unloaded is shown in Figure 86.
METHOD OF LOADING
Remove both turnbuckle hooks from each side of bolsters and slide them into ends of bolsters.
Place the "Movable Center Plate" flush with the edge of the bolster so that center plate is in the dead center of the
bolster. (This is important to provide for necessary slack action in the cars.)
The breech end of the gun barrel must be placed on the bolster with the "Fixed Center Plate" and must always lead
in the direction the car is moving.
The gun barrel must be so placed on both bolsters that the center of gravity of the barrel Is directly over the center
line of car coupling, so that each car will carry approximately one-half the weight of the gun barrel.
Clamping blocks over gun barrel at each bolster must be placed through rods and drawn down tight to firmly secure
barrel.
Center Clamp, Item "M", must be placed around gun barrel in position indicated on print over burlap and nuts on
front and back rods drawn up tight.
Breech end of gun barrel must be covered with canvas and held in place by band, Item "N", and breech block, Item
"O".
Nuts on rods through breech block, Item "O", and breech block plate, Item "P", must be tightened simultaneously
so that the bolster is square with car when the rods are securely tightened.
Muzzle end of gun barrel must be covered with canvas held in place by band, Item "Q", and muzzle block, Item
"R".
Tighten the nuts on the rods at muzzle block sufficient to take up slack, then move the cars forward and backward,
measuring the distance the "Movable Center Plate" moves past the bolster edge on each side, add them together-divide
by two, then set the bolster in this center of the "Movable Center Plate" and tighten up the muzzle rod nuts
simultaneously so that the bolster is square with the car when the rods are securely tightened.
All rods must be double nutted.
If necessary on account of length, to protect muzzle end of gun barrel, a fiat car of the required length should be
used as an idler.
Cars carrying major calibre gun barrels should be placed on the head end of a train to avoid slack action and
should move at a speed not to exceed 30 miles per hour with the end of the barrel always leading in the direction the
train is moving while in road movement.
E-108.6
