may be erected. When cars are needed to carry commodities requiring
protection from the weather or pilferers, the flatcar can be
converted to a boxcar by the addition of sides, ends, doors, and
roof. After the flatcar has been converted to either a gondola or a
boxcar, the weight of the lading is still carried by the bed of the
Superstructure units provide rigidity but do not support any
appreciable amount of weight.
Tank cars of the fleet are partially assembled by the car
manufacturer who attaches the tank unit to the car underframe along
with the outlet and safety valve assemblies and dome cover.
remaining assembly can be done in the field.
In addition to the knockdown cars described in paragraphs 2.11
some equipment built for special purposes are included in the foreign
This section discusses this rolling stock and, in
addition, some of today's newer developments in rail equipment.
Some 80-ton flatcars are included in the oversea fleet for
carrying ordnance and engineer equipment weighing more than 40 tons.
An example is seen in figure 2.10. Similar to the 40-ton flatcars,
only larger, these cars are designed to meet most railway operating
restrictions in a theater.
They are shipped knocked down and are
packed for easy assembly; however, converting them to a gondola or a
boxcar is not planned for at present. Because of their greater load
capacity, each car is mounted on two 6-wheel trucks, three axles per
truck, to avoid exceeding the low axleload limit on foreign railway
track, bridges, and other rail structures which are designed to
support a certain amount of weight per axle. With the 6-wheel truck,
weight is distributed evenly over a greater area than with a 4-wheel
truck, and more weight can be supported.
The 80-ton flatcar is
designed to operate on standard- to broad-gage railroads.