Signals and Speed limits

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Signals and Speed limits

Postby MBTA F40PH-2C 1050 » Wed May 19, 2004 6:38 pm

today, i saw an MBTA train #820 and i have a question about its operation.
#820 pulled out of Attleboro on Track 4 and approached Holden interlocking, but it had a stop signal and had to wait for the late #174. that went by and by the time the T began to move form Track 4 to Main track 2, the regional had already cleared three blocks.

So the signal aspect that the T recieved before leaving Track 4 was an Approach Limited (yellow over flashing green) adn he was procedding at 45 mph.

the next light was an Approach light, but about half a mile before the T passed it, the light turned to "cab speed" (flashing green) and the T began to accelerate before it had passed the light.

Now my question is, wouldn't the engineer have to continue on at 45 mph until he passed the "cab speed" light and then proceed at the speed shown?


Anopther question, what is the "cab speed" (flashing green) speed? 60?
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Postby AEM7AC920 » Wed May 19, 2004 9:34 pm

Well the cab speed flashing green would give you 0, 60 to 80 mph depending on the tracks speed F40 if you dig out your Norac on page 76 it says Cab signal Aspects on the top and it shows that the cab sig speed for flashing green is 0, 60, or 80. In the cab of the Geep the dot with the 60 or 80 would be lit. As for the 45 mph i'm thinking the engineer would have to wait until the end of the trains passes the signal to start picking up, have to do some more reading on that. :wink:
AMTRAK HAWK DETECTOR TRACK 1 NOOO DEFECTS OUT!
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Postby CSX Conductor » Thu May 20, 2004 10:48 pm

culd have exceeded 45 MPH as soon as the cab signals and ACSES displayed a more favorable aspect than Approach Limited......unless of course a less favorable signal was visible on wayside signal, then you would operate on the more restrictive, i this case being Limited Speed.

F40, I apolgize if I read your question or the scenario wrong.
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Postby CSX Conductor » Thu May 20, 2004 10:51 pm

just re-read it.................. if the signal went up to a Cab Speed signal, the engineer does not have to stay at Limited Speed. Notch it out!!! lol

Perhaps you are thinking of the one train length or 500 feet rule....which applies to Restricted Speed changing to a more favorable signal in Cab Signal territory

http://www.vnerr.com/training/NORAC_Signal_Rules.htm
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Postby MBTA F40PH-2C 1050 » Fri May 21, 2004 5:09 pm

so if a train was going along the line, and he started with a Approach light, and the next signal was a Approach Limited, but changed to Clear, once the SDU (speed display unit) showed clear, the engineer can begin to increase speed before he passed the clear light?
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Postby CSX Conductor » Sat May 22, 2004 1:56 am

Roger !!!
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