Speed Restrictive Signals

[welshdragon]

This might seem pointless, but i would like to see signals that can restrict a train's speed, is it a possibility?

[Conditional Zenith]

It's been suggested before. You may also like to check out the Routemarker patch.

[michael blunck]

[...] i would like to see signals that can restrict a train's speed, is it a possibility?

You mean slowing down a train to a certain speed at a signal? That´s totally different from having signals which only allow passing trains travelling at a certain speed. The latter exists in TTDPatch and has been discussed in OTTD quite a couple of times. The former is unknown to both.

regards
Michael

[Eddi]

i'd much rather see this as part of the orders.

"go from waypoint A to waypoint B at 80km/h"

[dihedral]

what would be the point of being able to tell how fast the train is allowed to go?
my guess is you dont even play with wagon speed limit enabled
does it not make more sense to be able to 'filter' which trains travel on which tracks, and perhaps filter by speed?

[Eddi]

is it so difficult to wrap your head around the fact that different people play the game differently? a "filter" is only ever going to help you, if you actually have multiple lines. for synchronising speed of different trains on one single line, forcing the speed limit is much better suited. also, it could help with scheduling the trains according to a fixed timetable, even if you upgrade engines. you can then fine tune the schedule to the new speed when all vehicles were replaced.

PS: i have no idea what you want to say with the wagon speed limit

[dihedral]

ah - yes, makes sense
i had asked not to say it was a stupid idea, just that i did not understand the reason as to why you would want to limit the trains to a speed.

the thing with the wagon speed limit is that if you dont enable it, your trains can go max_speed of the loc, and then wanting to limit trains to a certain speed again would defeat the purpose of disabling wagon speed limits (imo at least)

[Conditional Zenith]

I should have read more carefully, I thought this was another "I want slow trains to all use the side track".

[welshdragon]

In my case it would be useful for station approaches and sharp curve warnings, i feel that the way the trains just shoot into station approaches is not realistic, many UK stations have 30mph limits on the approaches to stations, so you could have a mainline train travelling at say 125 mph drop to 70 before the first signal , then to 50 by the second, and 30 bu the crossovers into the stations.
It would also be more realistic for those of us who know the speed limits of lines.

[SirXavius]

I think this is an excellent suggestion, mostly since it's the most feasible (just waiting for an inspired programmer!). There are times when i'd like to be able to sync my trains with even more detail than the timetables allow based not on waiting but on moving. This way trains can clear their lanes so an approaching train won't hafta wait for a light change at an intersecting track. Or i can sync trains to roll up right as the one ahead of it is timetables out of the station, so as not to block intersecting roads.

How would one set this up for code change?

[Kanibal]

I think this would be excellent! I have lots of mainlines and routes running different trains and it always bothers me to see the majority of trains cruising at say 70 and then one trying to do 80, catching up, stopping, slowly accelerating again and creating a slow patch where it just stooped.

It would be so much nicer to be able to say for this section of track between these 2 way points cruise at 70 like the rest.

[Toni Babelony]

Agreed. This would come in very handy for line-balancing at some parts where freight and passenger traffic are on the same route. Furthermore, programmable signals would also be quite nice next to this feature... However, I don't think the Devs. weren't too pleased with this feature.

[welshdragon]

I can see why the devs don't like it (it's making it more realistic), but then again if i could code (i can't and never will be able to) i'd do it myself, but i still think there is a case, ok, so perhaps not with signals, but what about using waypoints?

*edit* seems a speed post would be preferred by the devs

[Rubidium]

Really... how good people here are in taking stuff totally out of context.
1) when there is ONE developer that doesn't like it due to 'realism' it doesn't mean ALL of the developers dislike it
2) when ONE developer doesn't need it and doesn't fancy implementing it it doesn't mean that NONE of the developers might implement it
3) when SOME developers like an idea it doesn't mean that they will implement it

[belugas]

Shall we get the record straight?
Shall we?

[12:24] <@Rubidium> ofcourse "I don't need it and thus don't intend to code it" ends up with "the devs don't like it"

[12:26] <@petern> setting speed limits could have advantageous effects on traffic flow, possibly

[12:28] <@petern> signals are signals
[12:29] <@petern> would make more sense to do that sort restriction in the order list
[12:29] <@Belugas> agreed
[12:30] <@Belugas> but i guess people are influenced byt the way of the Patch

[12:32] <welshdragon> petern: some of us are lazy and want the game to do it itself
[12:33] <@petern> persuasive argument that

[12:38] <@Belugas> i'd rather see something new for the task than a reuse
[12:38] <@Belugas> i think that Richk brough up the notion of speed post or something like that
[12:39] <Swallow> You mean the routemarkers patch?
[12:39] <@petern> speed post would make sense, it doesn't interfere with waypoints or orders, and, erm, happens to be a bit more realistic

[welshdragon]

Fair enough.

[michael blunck]

[12:28] <@petern> signals are signals
[12:29] <@petern> would make more sense to do that sort restriction in the order list

O làlà. Please check your signal books. Today in almost every representative country railway speed restrictions are signalled via light signals.

Well, perhaps not in the U.K.: "The difference is British signals do not know speed signalling at all." http://en.wikipedia.org/wiki/German_railway_signalling

regards
Michael

[Eddi]

actually, i think there are two entirely different suggestions to be handled here:

1st:

for synchronising speed of different trains on one single line, [one should be able to force] the speed limit

this is imho useful to do in the orders of a train.

2nd:

[impose a speed limit] for station approaches and sharp curves

this could be done e.g. on making a PBS reservation. (not the best idea, but the only way where you can easily predict the path that a train will take)

For this to work one would have to find a way to suitably define what is a "switch" and which one is the "branching" part of a switch. Each railtype would then define a speed limit for each curve radius, and for straight and branching paths through a switch. Upon reserving a PBS path, the speed limit for the train would be the lowest speed limit on the reserved path (switches, curves, bridges, ...). the train acceleration code then could be extended to slowly decelerate to the target speed. Whether you then get the signals to actually show this speed limit is a totally different issue.

These speed limits would be forced upon the player (as in, similar to wagonspeedlimits). the problem with this approach might be, that people could avoid these restrictions by placing a signal in the middle of a curve, or by placing block signals.

examples for different railtypes could be:

1. branch line
   • axle weight: max. 15t
   • track speed: 60km/h
   • curve speed (2*45°): 50km/h
   • curve speed (90°): 30km/h
   • switch speed (straight): 60km/h
   • switch speed (branch): 40km/h
2. main line
   • axle weight: max. 18t
   • track speed: 120km/h
   • curve speed (45°+straight+45°): 90km/h
   • curve speed (2*45°): 60km/h
   • curve speed (90°): *forbidden*
   • switch speed (straight): 100km/h
   • switch speed (branch): 60km/h
3. modern main line
   • axle weight: max. 25t
   • track speed: 200km/h
   • --- some arbitrary values for longer curves ---
   • curve speed (45°+straight+45°): 90km/h
   • curve speed (2*45°): 60km/h
   • curve speed (90°): *forbidden*
   • switch speed (straight): 120km/h
   • switch speed (branch): 80km/h
4. high speed line
   • axle weight: max. 25t
   • track speed: 350km/h
   • --- some arbitrary values for longer curves ---
   • curve speed (45°+straight+45°): 120km/h
   • curve speed (2*45°): *forbidden*
   • curve speed (90°): *forbidden*
   • switch speed (straight): 300km/h (switches would have insanely high maintenance cost)
   • switch speed (branch): 150km/h

[peter1138]

[12:28] <@petern> signals are signals
[12:29] <@petern> would make more sense to do that sort restriction in the order list

O làlà. Please check your signal books. Today in almost every representative country railway speed restrictions are signalled via light signals.

Hehe, actually that bit of quote was about restrictions on pathfinding rather than speed limits

[Conditional Zenith]

I think richk's speed limit idea was to disallow trains that couldn't travel a certain speed past the post (ie. a minimum speed, rather than a maximum speed like is suggested here). This evolved into the routemarker system (so you could put coloured markers on the track and trains of that colour would avoid that track if they could). But they are different concepts, this suggestions is about slowing trains down, the routemarker/old speed sign idea is about forcing trains to use a different track (without heaps of waypoints).

While this doesn't address all the issues described here, another old idea is yellow signals (which I think existed as a patch at one point), which slowed trains down if later signals were red, rather than full speed until they hit a red.