Signal rules Vs. Signal hardwaregreenspun.com : LUSENET : ACL and SAL Railroads Historical Society : One Thread
I recently obtained a 1962 SAL rule book. The signal aspects in the book show only two possible colors in the bottom head of a three-head signal: red or yellow (flashing yellow also used). This has me baffled because I remember seeing three-head signals with three lights in the bottom head. There is a photo of one on page 23 of William E. Griffin, Jr.'s SAL book (a rear view but it looks like each head is of the three light type). Anyone know what the third light was for in the bottom head? What color was it?
The rule book shows only one indication requiring a three-head signal: Medium Approach. All other indications can be shown on either a one or two head signal. This indication seems most appropriate for a meet at a power operated siding. However many sidings were controlled by two head signals. Since there is no Medium Approach indication for a two head signal, which indication did SAL use for a meet at such sidings?
I've put the signal aspects on an HTML page and can send it as an e-mail attachment to anyone who wants one. Just let me know (send a separate e-mail to me.)
-- Jim Coviello (email@example.com), March 12, 2000
Just to add one thing to Harry's excellent answer-the fact that a signal head has provisions for three lights does not necessarily mean that it has three lights. Many of the three light fixtures had one or even two of the lights blanked out. This allowed the use of one type of fixture for all various indications.
Another factor is that while one signal head could provide the necessary indications, most railroads used two or more heads for safety purposes. As an example, on the New York Central, a clear indication on 1930's vintage signals was a green over red. The double signal was a means of ensuring that the proper indication was given and that if a signal showed only one light, it was an easy means of telling engine crews that there was something wrong and that they should treat it as the most restrictive indication a signal could show.
-- Michael W. Savchak (Savchak @MNR.org), March 13, 2000.
Jim: I don't have my SAL rule book handy, so I'll speak in generalities. Rule 287 requires a green on the bottom target. For high masted signals this is two reds over a green on the bottom target. RULE 287 Indication - Proceed; Slow Speed within interlocking limits or through turnout or turnouts.
Name - Slow clear.
Slow speed is a speed not exceeding 15 MPH. N&W's Rule 287 also made this note: Slow speed applies until leading end reaches oposing home signal when route is lined for straight track movement. Slow Speed applies for entire movement through turnout or turnouts.
What signal did SAL trains get to enter a siding ? That depended on whether or not the siding was a SIGNALLED siding. SIGNALLED sidings were bonded and usually were equipped with turnouts good for 25-35 MPH. Signalled sidings were noted in SAL's timetables under SPECIAL INSTRUCTIONS. Provided there was no intermediate signal before the end of the siding, the entrance signal would display MEDIUM APPROACH -- PROCEED AT NOT EXCEEDING MEDIUM SPEED PREPARED TO STOP AT NEXT SIGNAL. In other words, a train could enter the siding at 25-35 MPH to clear the main track, but it had better be able to stop at the other end.
SAL also had, for lack of a better term, some non-signalled sidings. Ryan on the Richmond Sub was one. These sidings were NOT bonded and were usually entered at a speed not exceeding 15 MPH (through power operated switches). The signal at the entrance displays RESTRICTING, Rule 290 which is red on the top target and yellow on the bottom target. Remember, since the siding isn't bonded, there can be a train (or a car)just beyond the clear post and you'll still get a RESTRICTING to enter the siding. This puts the onus on the crew entering the siding to keep their eyes peeled.
-- Harry Bundy (firstname.lastname@example.org), March 12, 2000.