This is from the 1909 Car Builder's Dictionary, under Interchange Rules. This governs repair splices to sills. 1895 edition did not allow center sill splices, but now they are allowed with a reinforcing timber as shown in figure 9A. But I read from this that center sills can't be spliced right in the center. Cross tie timbers are also known as needle beams.
Rule 65. Draft timbers must not be spliced. All longitudinal sills may be spliced once, with the exception of center sills, which may be spliced at both ends.
Not more than two adjacent sills may be spliced at the same end of car. The splice may be located either side of body bolster, but the nearest point of any splice must not be within
12 inches of same, excepting center sills, which must be spliced between body bolster and cross-tie timbers and not within 24 inches of either. Longitudinal sills other than center sills where less than 12 inches in depth, the plan shown in Fig. 8 is to be followed. When the sills are 12 inches or more in depth the plan shown in Fig. 9 is to be followed. When center sills are spliced the plan shown in Fig. 9a is to be followed. The size of horizontal or cross bolts shown in Fig. 9a should be 5/8 inch.
