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| Two-thirds rule 27/03/2014 at 18:29 #57912 | |
Jan
889 posts |
As far as I can remember, none of the Southern region sims currently implements the two-thirds rule for freight trains. Was that a deliberate decision, or was it just one of those things that just happen (or in this case rather not happen B))? In theory it shouldn't be too difficult too implement, as it's just a matter of setting a load of differential speed restrictions according to the conversion table given in the Sectional Appendix (page 63, warning: large PDF). What probably complicates things though is that a number of trains are exempt from the two-thirds rule, so it's not just a matter of differentiating based on the "Use freight linespeeds" box. Maybe the custom sim-specific speed classes could be put to use here, e.g.: Sim 1: Freight trains which are completely exempt from the two-thirds rule, i.e. Class 4 trains, and which only need to obey conventional differential speed restrictions. Sim 2: "Authorised" Class 6 & 7 trains to/from the Channel Tunnel, which are exempt from the two-thirds rule on certain routes only, and are subject to blanket speed restrictions within London* Should the idea go forward, I apologize in advance to the developers who have to enter all those additional speed restrictions into the sim data... :whistle: * Which creates some small anomalies, as I've found two locations where the blanket speed restriction yields a lower speed limit than that imposed by the two-thirds rule :blink: Two million people attempt to use Birmingham's magnificent rail network every year, with just over a million of them managing to get further than Smethwick. Last edited: 27/03/2014 at 18:31 by Jan Log in to reply |
| Two-thirds rule 27/03/2014 at 18:30 #57913 | |
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DanC
53 posts |
Just for those of us not in the know - could you explain briefly the two-thirds rule? :whistle:
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| Two-thirds rule 27/03/2014 at 18:34 #57914 | |
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Jan
889 posts |
Sorry. Briefly put, on the Southern region signal spacing is mostly based on the braking curves for passenger trains. Therefore freight trains need to run at a lower speed (two thirds of the permissible line speed, hence the colloquial name of the rule) in order to be able to stop in time in front of a red signal. Two million people attempt to use Birmingham's magnificent rail network every year, with just over a million of them managing to get further than Smethwick. Last edited: 27/03/2014 at 18:40 by Jan Log in to reply The following users said thank you: DanC, maxand |
| Two-thirds rule 27/03/2014 at 18:45 #57915 | |
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DanC
53 posts |
Thanks :side:
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| Two-thirds rule 27/03/2014 at 20:33 #57917 | |
DriverCurran
683 posts 
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As the developer of Lancing, I have just checked and the freight speeds in that simulation are set to the two thirds rule.... Paul You have to get a red before you can get any other colour Log in to reply |
| Two-thirds rule 27/03/2014 at 21:09 #57919 | |
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Jan
889 posts |
:blush: That's one I've overlooked then... that still leaves the matter of Class 4 trains there though, which should be exempt from the two-thirds rule. Although I admit that in the case of Lancing that's all probably rather academic anyway, as at least with modern era timetables, the amount of freight there is rather negligible. It's probably more relevant in the case of Southampton or the Victorias (both), where I'm quite certain that the two-thirds rule currently isn't simulated. Two million people attempt to use Birmingham's magnificent rail network every year, with just over a million of them managing to get further than Smethwick. Last edited: 27/03/2014 at 21:17 by Jan Log in to reply |