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Re: LA Times story on Metrolink vs BNSF incident at Rialto [link]
Author: Dr Zarkoff
Date: 11-23-2008 - 01:42
>That many existing ATS or ATC systems (especially on freight trains) currently allow the engineer to merely acknowledge the restrictive aspect without actually enforcing the it, and then supervising the braking,
Huh? The train control on the SFOBB would stop you automatically (big hole) if you didn't slow down upon receiving a restrictive indication. If you were on a "green", which was displayed as "35" in green numerals, and received a "yellow 25" or "yellow-red 17", a bell would start ringing and you had 2 1/2 seconds to shut off the controller and apply the brakes or the TC would put you into big hole. Same was true if you had a "yellow 25" and it dropped to a "yellow-red 17". If any permissive indication dropped to "red 11", then you would get a loud warning buzzer too, and you always had to acknowlege a "red 11" (press on a pedal). This is right out of GRS Handbook 16
The last GG1 I rode was very similar, to my amazement, although it would go into a full penalty application rather than big hole. At the time, the NEC used the essentially the same cab signal system which was on the SFOBB, although the display in the cab was position light rather than speed indications (the SP's train control displays for the SFOBB are identical to those in a GG1, except that the indications are given as speeds). There were places where you would receive a rate code for a slower speed which was track related rather than a signal indication requirement. With the MP-54s, on the other hand, there ware no provisions for automatically stopping should the engineer acknowlege a restrictive indication and not slow down.
The reason for the similarity between the SFOBB and NEC (PRR) installations is that the PRR wrote the specs for coded cab signals and then gave them to both GRS and US&S. Any other railroad which used this type of coded cab signals got essentially the same system (CRI&P, SP, PRR, P-R.S.L. -- this is a very dated list. The AT&SF had them out of Chicago, and I think the Q did too, but I could be mistaken).
ATS (inductive, intermittent, tripper arms, whatever) is a completely different story.
Huh? The train control on the SFOBB would stop you automatically (big hole) if you didn't slow down upon receiving a restrictive indication. If you were on a "green", which was displayed as "35" in green numerals, and received a "yellow 25" or "yellow-red 17", a bell would start ringing and you had 2 1/2 seconds to shut off the controller and apply the brakes or the TC would put you into big hole. Same was true if you had a "yellow 25" and it dropped to a "yellow-red 17". If any permissive indication dropped to "red 11", then you would get a loud warning buzzer too, and you always had to acknowlege a "red 11" (press on a pedal). This is right out of GRS Handbook 16
The last GG1 I rode was very similar, to my amazement, although it would go into a full penalty application rather than big hole. At the time, the NEC used the essentially the same cab signal system which was on the SFOBB, although the display in the cab was position light rather than speed indications (the SP's train control displays for the SFOBB are identical to those in a GG1, except that the indications are given as speeds). There were places where you would receive a rate code for a slower speed which was track related rather than a signal indication requirement. With the MP-54s, on the other hand, there ware no provisions for automatically stopping should the engineer acknowlege a restrictive indication and not slow down.
The reason for the similarity between the SFOBB and NEC (PRR) installations is that the PRR wrote the specs for coded cab signals and then gave them to both GRS and US&S. Any other railroad which used this type of coded cab signals got essentially the same system (CRI&P, SP, PRR, P-R.S.L. -- this is a very dated list. The AT&SF had them out of Chicago, and I think the Q did too, but I could be mistaken).
ATS (inductive, intermittent, tripper arms, whatever) is a completely different story.
