TY  - BOOK
AU  - Rockwell,Ray Robert
TI  - Railroad track circuits and interlocking,
AV  - TF630 .R6
PY  - 1933///]
CY  - Scranton, Pa.
PB  - International textbook company
KW  - Railroads
KW  - Signaling
KW  - Block system
KW  - Interlocking systems
ER  -