Steve "Papa" Eastman posted:
The basic Lock-on patent was awarded to Louis Caruso <http://pdfpiw.uspto.gov/.piw?d...37%2526RS=PN/1542337>
These special Lock-ons were developed for Lionel new accessories introduced in the mid-20s. The left one was furnished with "0" gauge 080 Semaphore; center was provided with the Standard gauge 80 Semaphore; right was provided with the Standard gauge 78 Block signal and the three-wire 82 Semaphore (there was also an "0" gauge version of this Lock-on for the 078 and 082 signals).
Ron M