Why isn't the Honiton line displayed as OTW?

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Why isn't the Honiton line displayed as OTW? 24/06/2014 at 08:27 #61961
maxand
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1637 posts 		Unlike the other OTW (One Train Working) lines in this sim, the Honiton (hollow track) line remains grey and doesn't display in green when unoccupied, or red when occupied.

It's no big deal, as the pointer table below it advises whether or not the line is occupied, but I was just wondering why the developers chose to do it this way.
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Why isn't the Honiton line displayed as OTW? 24/06/2014 at 08:51 #61963
BarryM
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2158 posts 		It is simulating the way it was in real life. No track circuits!

Barry
Barry, Sydney, New South Wales, Australia
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Why isn't the Honiton line displayed as OTW? 24/06/2014 at 09:37 #61965
robert
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18 posts 		The line to Honiton is controlled by tokenless block, not one train working. Two very different systems
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The following user said thank you: maxand
Why isn't the Honiton line displayed as OTW? 24/06/2014 at 09:38 #61966
jc92
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3631 posts 		The section isn't OTW (where one train accesses what is effectively a long siding) it is tokenless block. In OTW sections, there will be an indication the train is in section, eg the token is missing, which has been represented with a hollow red track circuit. Tokenless block has the block instrument to show occupancy of the block instead.
"We don't stop camborne wednesdays"
Last edited: 24/06/2014 at 16:40 by jc92
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The following user said thank you: maxand
Why isn't the Honiton line displayed as OTW? 24/06/2014 at 11:37 #61973
maxand
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1637 posts 		Thanks for explaining that. I will need to read up tokenless block now.
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Why isn't the Honiton line displayed as OTW? 24/06/2014 at 16:10 #61984
Muzer
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718 posts 		" said:
The section isn't OTW (where one train accesses what is effectively a long siding) it is tokenless block. In OTW sections, there will be an indication the train is in section, eg the token is missing, which has been represented with a hollow red track circuit. Time less block has the block instrument to show occupancy of the block instead.
I believe I'm right in thinking that some real-life areas have some form of tokenless/staffless OTW, where the order of operation of track circuits/treadles on entry to the section determine its occupation. How is this occupation represented in real life, out of interest?
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Why isn't the Honiton line displayed as OTW? 24/06/2014 at 17:44 #61986
Stephen Fulcher
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2028 posts 		Muzer is correct - three relays which operate with the sequential operation of track circuits and treadles will control the release of the section.

The indication is basically driven off whether the (OTW)SR relay is up or down. If it is up the section will be clear, and if it is down it will be occupied.

The section from Penryn to Falmouth Docks indicates with a single white light in the box diagram for clear, and a single red for occupied.

The one at Exmouth Junction for Topsham to Exmouth is green panel lamps for clear and red for occupied, which seems to be a fairly common arrangement.
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Why isn't the Honiton line displayed as OTW? 25/06/2014 at 12:46 #62018
maxand
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1637 posts 		Thanks Muzer and Stephen. It continually amazes me how much variation there is in what I would have considered to be fairly standard implementation!
Last edited: 25/06/2014 at 12:46 by maxand
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Why isn't the Honiton line displayed as OTW? 25/06/2014 at 13:01 #62019
Ron_J
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329 posts 		There are at least two versions of Tokenless Block in use too - Scottish Region Tokenless dating from 1967 and the 'official' British Rail version as used on the Honiton line which came somewhat later. The two versions use very different instruments and circuitry to achieve the same thing. I think the Scottish Region version is the better of the two but I'm biased.
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Why isn't the Honiton line displayed as OTW? 25/06/2014 at 17:35 #62028
Stephen Fulcher
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2028 posts 		Max, the thing to remember with One Train Working is that in reality it is for dead-end lines, such as Topsham to Exmouth only.

Artistic licence in SimSig on the Barnstable Branch was used in the simuation. This line actually uses No Signalman Key Token working in reality, which was not easily reproduced when the simulation was first written, although is now possible in the new core code, as demonstrated by the Blaenau Ffestiniog section in the updated North Wales Coast.
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