NW-Mailing-List Digest, Vol 221, Issue 41
NW Mailing List
nw-mailing-list at nwhs.org
Sat Jan 28 22:36:15 EST 2023
Forgive my impertinence, oh great ones of N&W knowledge…..
A minor correction is offered to the formidable Abram Burnett, farm-grade turnip technician of impeccable reputation:
Title 42 CFR is Public Health, perhaps a slightly different cure for insomnia.
49 CFR Parts 200 - 299 deal with all things under the purview of the FRA;
> On Jan 28, 2023, at 9:11 PM, NW Mailing List <nw-mailing-list at nwhs.org> wrote:
> I think Mr. Lisle's comments about lights on main track switches may refer to the switches of interlockings on the Shenandoah Division, where he worked.
> Switches in interlockings have never had switch markers installed, on any railroad, to my knowledge. Given the principles of interlocking, the Home Signal cannot be displayed for a movement until all switches in the route are in the proper position and indicate as locked-up (i.e. secured) so that the points cannot move, there are no opposing movements authorized by signal indication. and there are no broken rails in the route. Therefore, a favorable indication on the Home Signal makes switch markers on the individual switches unnecessary. This has been the case since the days of pipe-connected manually controlled interlockings.
> As to Main Track hand operated switches OUTSIDE of Interlockings, but in CTC territory (like the Shenandoah Division,) I agree with Mr. Lisle that the N&W did not light them.
> Example: Take the case of North Roanoke and Cloverdale, two adjacent interlockings in CTC territory. The southward home signal at Cloverdale cannot be cleared, and the northward home signal at North Roanoke cannot be cleared, until the following conditions have been met:
> 1. Opposing movements have been prevented by the logic of the signal system (i.e. setting the opposing home signal to Stop.)
> 2. All switches within interlocking limits must indicate as being in the proper position and locked up (electrically.)
> 3. All hand switches between the two interlockings must indicate as closed and electrically locked.
> 4. There must be no broken rails
> These are standard requirements for any Traffic Control system, and they have been in effect since the 1930s when the ICC published its RS&I book of regulations (Railroad Signals and Interlockings.)
> Given all this, you can see how a lengthy chunk of main track, between interlockings (like North Roanoke and Cloverdale,) operated by a Traffic Control signal system could be considered a very, very long interlocking. In both cases, all the same safety requirements must be satisfied. And the N&W thought that was good enough, and dispensed with switch markers.
> If you suffer from insomnia, call the FRA and have them send you a copy of the RS&I regulations (which are now published in Code of Federal Regulations, Title 42.) Guaranteed cure for insomnia.
> -- abram burnett,
> farm-grade turnip technician
> NW-Mailing-List at nwhs.org
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