Secondary speed limits

[npcleary]

Probably me just being thick again but what is the secondary speed limit for? Primary speed limit - no problem, but I can't seem to find any references to the secondary one other than where it is input etc...

Thanks
Nick

[mearle73]

On the real railway you can have 2 line speeds one for passenger the other for freight trains.

[npcleary]

That's what I originally thought but when I run a scenario driving a "slow freight" the indicated speed limit shows the primary limit of 50 rather than the secondary limit of 30. I've double checked the speed limits for the section of track which is also line type "freight" and it doesn't seem to make any difference .

[Oldpufferspotter]

This is only a guess as I am only just starting to use speed limits on my own route.
In France there are often two speed limits, one for TGV trains, and the other for ordinary express trains, each sign having the two limits showing one on top of the other. I am not sure if we have that sort of thing in this country. Tilting trains, and ordinary trains perhaps?
Does RS have dual restriction signs for its continental routes perhaps?
Do we have a temporary speed restriction sign in RS? If so that would perhaps pick up the lower figure, or secondary speed, when we place the sign?
Just guesswork on my part at the moment.
regards Ted.

[AndyUK]

I am not sure if we have that sort of thing in this country. Tilting trains, and ordinary trains perhaps?
Does RS have dual restriction signs for its continental routes perhaps?

Yes there are differential speed limits in this country, most often setting a lower limit for freight, but also higher limits for HSTs and Sprinters etc. I think I've seen one in RS in the Newcastle - York route but I could be wrong. The RS Cajon Pass route has lots of them, but I believe they are labelled wrongly as the signs shows the lower limit alongside the letter "P" and the higher alongside "F" rather than the other way round.

Also the F3 Driver's Guide only ever shows the higher limit but, if you run a scenario, the scenario summary that you get when you finish seems to mark you correctly. In a freight train you get "busted" for exceeding the lower limit, even though it's labelled "P", but in a passenger train you only get done for exceeding the higher limit.

Andy L

[npcleary]

Also the F3 Driver's Guide only ever shows the higher limit but, if you run a scenario, the scenario summary that you get when you finish seems to mark you correctly. In a freight train you get "busted" for exceeding the lower limit, even though it's labelled "P", but in a passenger train you only get done for exceeding the higher limit.

Andy L

Andy, I've just tried running a slow and a standard freight at speeds in excess of the secondary limit but below the primary limit and didn't get "busted" ! I'm still a little baffled as to what it's there!

Nick

[AndyUK]

Nick,

Are you running those on your route, or Cajon Pass? Also bear in mind that as far as I can tell you don't get "assessed" in free roam scenarios, only Standard Scenarios.

The primary and secondary limits certainly seem to have some effect on Cajon Pass, it's just that they seem to be labelled incorrectly on the trackside signs, and the F3 Driver's Guide never shows the lower one.

Andy

[npcleary]

Hi Andy, I ran the freights in standard scenarios on my own route. I've installed the Cajon Pass route but have yet to try it - I'll experiment a bit today and see what happens...

Nick

[npcleary]

Andy, Just reran the standard scenario on my own route and got "busted"! Also walked down the road to the WCML (it's only a couple of hundred yards away) and had a look at the signs there - dual speed signs! Teach me to keep my eyes open . Looked at the Cajun route and see what you mean about the dual signs being the wrong way round... Presumably the same applies to the "Speed Sign Double UK" which shows the secondary speed on top?

As I am building a steam era route I am probably going to have to ignore secondary limit signs and just rely on route knowledge if I'm driving a freight. My memory is failing me but were there dual signs about in the steam era?

Nick

[AndyUK]

Nick,

The design of the the RailSim UK differential speed limit signs seems to be correct in having the lower (secondary) limit at the top. See here for all you could possibly need to know about trackside signs! http://www.rgsonline.co.uk/docushare/ds ... RT7033.pdf

I think the US signs should be the same, i.e. lower on top, it's just that they need to swap the "P" and "F" round. RSDL have noted the problems with primary and secondary limits and the F3 Driver's Guide and are putting it on the list to be investigated http://www.railsimulator.com/en/node/3629

Not sure how differential limits were handled in the steam era. I seem to remember reading somewhere that until quite late on speed limit signs in general were few and far between and a lot more reliance was placed on the train crew's knowledge of the sectional appendix!

Andy L

[npcleary]

Nick,

The design of the the RailSim UK differential speed limit signs seems to be correct in having the lower (secondary) limit at the top. See here for all you could possibly need to know about trackside signs! http://www.rgsonline.co.uk/docushare/ds ... RT7033.pdf

Andy, thanks for the link - comprehensive or what ! Another doc for the lever arch file..... Just been for another look at the WCML down the road and they are separate speed signs next to each other not dual ones. Having said that, it is a mess down there at the moment with the 4 tracking work...

Not sure how differential limits were handled in the steam era. I seem to remember reading somewhere that until quite late on speed limit signs in general were few and far between and a lot more reliance was placed on the train crew's knowledge of the sectional appendix!

I can't find any trace of steam era dual speed signs so I think you're right - having built the route I'm going to have to learn it! All fun...

Thanks for your help....Nick

[mbtech22]

Being someone who can remember the "steam era", I don't think there were such things as differential speed limits at that time. Speed limits appear to have been far more arbitrarily applied and over wider areas than these days where every "second counts". Hence for example the SR mainline to Plymouth was limited to 40mph after Lydford even on the few straight sections.
In this country (UK) speed limits are usually applied for reasons of limiting track forces, as well as the more obvious risk of overturning. Therefore lighter trains such a passenger coaches can go round curves faster than a more heavy freight train. These forces also apply vertically and so a differential speed limit may also be applied say to a weak bridge. Therefore the speed differences are not always applicable to the same train classifications some are Passenger/Freight, some are Tilt/non-Tilt, others are bogie/2-axle and there are also many which are Sprinter/non-sprinter or EMU/other. Also in the case of two of the RS routes HST/other.
I am lead to believe that in America where generally freight traffic is predominant the lines are built to carry high axle load traffic and therefore a possible reason for the passenger speed being lower may be one of comfort. Passengers being more susceptible to high lateral forces than freight.

Mark Brinton

[AndyUK]

I am lead to believe that in America where generally freight traffic is predominant the lines are built to carry high axle load traffic and therefore a possible reason for the passenger speed being lower may be one of comfort. Passengers being more susceptible to high lateral forces than freight.
Mark Brinton

Mark,

You could be right, but I've just checked the MSTS Marias Pass route and on that the limit for passenger is higher than for freight, and RSAdam in a similar thread on the RailSim site forum believes that the lower limit should apply to freight on the Cajon Pass route. I guess that unless someone with first hand knowledge of the route in question joins in we can only speculate.

Andy L