that is less than actual thickness shown in table 1 should not
(15) In stop-off cars each individual consignment
be used. Table 2 shows the species of wood most commonly
should be separately braced and blocked, where possible, in
used for bracing. It is recommended that medium woods be
order to reduce the requirement for restoring, blocking, and
used. The next larger commercial size should be used for
bracing constructed with soft woods. Table 3 shows the
standard sizes for soft and medium woods.
Lumber, Nails, and Nailing.
(6) Nails should not be used where they are in
(1) Properly seasoned lumber should be used for
direct tension, but in lateral resistance as shown in figures 3,
car bracing and blocking. Green lumber should not be used
as it does not have the strength or stiffness qualities of dry
lumber. Green lumber under certain conditions will give off
(7) Nails should be driven into the side grain of
quantities of moisture that can have harmful effects on some
lumber as this provides 50 percent more holding power than
commodities loaded in the car.
when driven into the end grain. All nails should be driven
(2) Lumber used for blocking and bracing should
be properly stored and protected from the elements to prevent
(8) Nails should be of sufficient length so that
rot or decay.
two-thirds of the length of the nail goes into the member
holding the point. Table 5 indicates sizes of nails, spikes, or
(3) When selecting the size of lumber for bracing
bolts to be used for various thicknesses of material.
and blocking, consideration should be given to the weight,
size, nature of the commodity to be secured within the car,
(9) Nails that will protrude beyond the thickness of
and the capability of the blocking and bracing to withstand
car sides or through the car floor must not be used, as they
impacts of up to 8 miles per hour.
cause damage to car equipment.
(4) All blocking and bracing material should be
selected from sound lumber free from crossgrain, dry rot, knot
c. Blocking and Bracing.
holes, checks, or splits that will affect its strength or interfere
(1) All floor blocking must be securely nailed to
(5) The dimensions shown in this manual for
car floors and reinforced with backup cleats (fig 3 and 6)
lumber to be used in the construction of center gates, end
extending over three or more floor boards. Backup cleats
gates, doorway bracing, and blocking are the nominal
should be of material not less than 2 inches by 4 inches and
dimensions for commercial sizes of lumber. Table 1 indicates
at least 18 inches in length.
the nominal and actual thickness of commercial lumber
generally used for this purpose. Lumber
Figure 3. Nails in lateral resistance in backup cleats
Figure 4. Nails in lateral resistance in staggered pattern.