Railroad track circuits and interlocking,
Rockwell, Ray Robert, 1885-
Railroad track circuits and interlocking, - Scranton, Pa., International textbook company [1933] - v, 74, 66, 58 p. illus., 2 fold. pl., plans (part fold.) diagrs. 20 cm.
34026352
Railroads--Signaling--Block system.
Railroads--Signaling--Interlocking systems.
TF630 / .R6
Railroad track circuits and interlocking, - Scranton, Pa., International textbook company [1933] - v, 74, 66, 58 p. illus., 2 fold. pl., plans (part fold.) diagrs. 20 cm.
34026352
Railroads--Signaling--Block system.
Railroads--Signaling--Interlocking systems.
TF630 / .R6