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Re: New on Jan 4 NTSB update re: Amtrak 501-Not Much New?
Author: theconductor
Date: 01-10-2018 - 08:36
Dr Zarkoff Wrote:
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> > Searchlight signals are not allowed with PTC
> anyway.
>
> Never heard this before. The demise of searchlight
> signals in favor of colorlight signals is more a
> case of eliminating redundant relays from the
> signal system, the relays being the searchlight
> mechanisms, and using the relays which control the
> mechanisms to control colorlights directly. Like
> all relays, the searchlight mechanisms are subject
> to periodic testing and have the added dager of
> the maintainer slipping and falling off the mast.
> Installing PTC also involves changing signal
> locations to something a lot furter apart, in
> order to reduce the number of signals to buy,
> install, and maintain.
That's because it's not true. As an example, the Sacramento Sub between Haggin and Binney is PTC with searchlight signals.
-------------------------------------------------------
> > Searchlight signals are not allowed with PTC
> anyway.
>
> Never heard this before. The demise of searchlight
> signals in favor of colorlight signals is more a
> case of eliminating redundant relays from the
> signal system, the relays being the searchlight
> mechanisms, and using the relays which control the
> mechanisms to control colorlights directly. Like
> all relays, the searchlight mechanisms are subject
> to periodic testing and have the added dager of
> the maintainer slipping and falling off the mast.
> Installing PTC also involves changing signal
> locations to something a lot furter apart, in
> order to reduce the number of signals to buy,
> install, and maintain.
That's because it's not true. As an example, the Sacramento Sub between Haggin and Binney is PTC with searchlight signals.
