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Author Topic: Why is it that older gamesaves don't allow you to buy certain locomotives?  (Read 809 times)

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Offline mammothim2906 england

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Hello James, I have been wanting to ask this question but haven't got the time to but, why is it that older gamesaves don't allow you to buy certain locomotives?

Gamesave: https://drive.google.com/open?id=1DXMGwvMf6Viq3DJl58MzpwHIJ7b1Tr7C

Offline Rollmaterial fi

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I think you'll need to be a bit more precise. Which specific vehicles are not available?

Offline jamespetts gb

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I am away from home this week so cannot access the saved game, but Rollmaterial is correct that you do need to be much more precise.

Also, you should check whether the depot type supports the type of locomotive that you are seeking to buy.

Offline mammothim2906 england

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What I mean is that certain diesel locomotives (bought from the all tractions depot (and a couple or even 1 locomotive from the Electric depot)) are disabled and when I hover over them a message comes up below (where the train info. is) saying "Too heavy!". Plus this only applys when the 120km/h max. speed track is in place. This issue applys to the following locomotives: The Class 56, 58, 60, 62, 66, 67, 68, 88, 90, 91 and 92 locomotives (the Class 88, 90 and Class 92 locomotives are electric locomotives only available from the electric traction depot).

Picture of proof (this is from an all tractions depot)


Offline jamespetts gb

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Re: Why is it that older gamesaves don't allow you to buy certain locomotives?
« Reply #4 on: September 01, 2018, 08:58:50 PM »
This means that the depot is built on track whose maximum axle load is too light for these locomotives. All that you need to do is upgrade the track beneath the depot (and, if necessary, also on the route on which they are to run).

Offline mammothim2906 england

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Wouldn't that be unfair because, people might not want trains running at 90mph (including if the line is in a densely congested area or at junctions)

Offline jamespetts gb

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I am afraid that I do not understand the point. How is it unfair that locomotives that are too heavy for the track on which the depot is constructed not to be able to use the depot?

Offline mammothim2906 england

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What I am trying to explain is that people may want to simulate real life loco-hauled services/freight trains and the locomotives/carriages which they want to use wont be available because of the weight of the track. If anything, I would change the weight settings for each line to allow the heavy locomotives/carriages/wagons to be purchased.

Offline jamespetts gb

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All that you have to do in that case is upgrade the weight of the track - I do not understand how this relates to the fairness of the game.

Offline mammothim2906 england

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I fully understand that but I build lines which are realistically meant to be ran at 75mph and not any faster (for example 90mph+)

Offline jamespetts gb

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Re: Why is it that older gamesaves don't allow you to buy certain locomotives?
« Reply #10 on: October 16, 2018, 11:01:58 PM »
I do not see how this relates to the fairness (i.e. balance) of the game - can you explain?

Offline Spenk009

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Re: Why is it that older gamesaves don't allow you to buy certain locomotives?
« Reply #11 on: October 17, 2018, 10:58:00 AM »
Could you please post the info to the rail segment under the depot? Once you've opened the depot, move the window out of the way, tap A and click again on the same spot. The info window for the tile will open, which should help us solve the issue.

Offline SuperTimo

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Re: Why is it that older gamesaves don't allow you to buy certain locomotives?
« Reply #12 on: October 17, 2018, 03:18:02 PM »
I fully understand that but I build lines which are realistically meant to be ran at 75mph and not any faster (for example 90mph+)

From someone who works in railway signalling In real life I can't think of any passenger lines that are limited to 75 Mph in the UK for their entire length. Speed profiles are not usually decided by track quality instead, as is the case in-game, the quality of the track is more a factor as to which rolling stock can use a line. So you might have a line that has a 75 Mph speed limit because the only rolling stock intended to use the lines are class 14Xs (pacers) which have a top speed of 75 Mph so the signalling is only designed accordingly. All of those locomotives you cannot select are heavy freight or express locomotives and so would be completely unsuitable for the type of lines you are talking about. These low speed lines are normally only as such due to the geography of the routes they take, for example lines in Cornwall. Most freight trains are limited to a maximum of 75 Mph regardless of what line they are using (I think goods vans can travel at line-speed but these are very rare in the UK today, container flats are only permitted at 75 Mph), some freight only lines may have very low speed limits since they are only used by one train at a time and a lower speed limit prevents wear to the track, in which case the speed limit would probably be as low as 20 Mph, which you can represent in game by using drive by sight working.
« Last Edit: October 17, 2018, 03:37:33 PM by SuperTimo »

Offline mammothim2906 england

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Re: Why is it that older gamesaves don't allow you to buy certain locomotives?
« Reply #13 on: October 17, 2018, 03:43:14 PM »
From someone who works in railway signalling In real life I can't think of any passenger lines that are limited to 75 Mph in the UK for their entire length. Speed profiles are not usually decided by track quality instead, as is the case in-game, the quality of the track is more a factor as to which rolling stock can use a line. So you might have a line that has a 75 Mph speed limit because the only rolling stock intended to use the lines are class 14Xs (pacers) which have a top speed of 75 Mph so the signalling is only designed accordingly. All of those locomotives you cannot select are heavy freight or express locomotives and so would be completely unsuitable for the type of lines you are talking about. These low speed lines are normally only as such due to the geography of the routes they take, for example lines in Cornwall. Most freight trains are limited to a maximum of 75 Mph regardless of what line they are using (I think goods vans can travel at line-speed but these are very rare in the UK today, container flats are only permitted at 75 Mph), some freight only lines may have very low speed limits since they are only used by one train at a time and a lower speed limit prevents wear to the track, in which case the speed limit would probably be as low as 20 Mph, which you can represent in game by using drive by sight working.

Okay true, but ignoring the fairness thing (James). I do want to run loco-hauled trains but with the track weight being to heavy. Its not possible, particularly when your trying to be realistic;y recreate the exact service with the exact loco/wagon/carriages.

Offline SuperTimo

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Re: Why is it that older gamesaves don't allow you to buy certain locomotives?
« Reply #14 on: October 17, 2018, 05:26:19 PM »
Okay true, but ignoring the fairness thing (James). I do want to run loco-hauled trains but with the track weight being to heavy. Its not possible, particularly when your trying to be realistic;y recreate the exact service with the exact loco/wagon/carriages.

Which line are you trying to recreate?

Offline mammothim2906 england

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Re: Why is it that older gamesaves don't allow you to buy certain locomotives?
« Reply #15 on: October 17, 2018, 05:50:05 PM »
Rural services, some services in Scotland and not trying to have ecessive speed on the approach to large terminus/hub stations

Offline jamespetts gb

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Re: Why is it that older gamesaves don't allow you to buy certain locomotives?
« Reply #16 on: October 17, 2018, 09:27:26 PM »
I am struggling to understand this request - it appears as if you are wanting to use track speed not as an economic constraint but as a means of changing the cosmetic appearance of speed. This is not how the pakset is intended to be balanced; if you want objects that have characteristics not intended for purely economically realistic balancing, you will have to create them yourself.

Offline mammothim2906 england

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Re: Why is it that older gamesaves don't allow you to buy certain locomotives?
« Reply #17 on: October 20, 2018, 07:50:02 PM »
Okay I understand what you are saying, but my point is that I want to have loco hauled passenger train/freight services using the locomotives and wagons which are too heavy for the 120 km/h (75 mph) track. However, one suggestion that I am putting forward (may need a new topic for this) is to have different types of track with different speed limits (e.g. 26 tonne track with a max. speed of 75 mph (120 km/h) or 22 tonne track with a max. speed of 105 mph (168 km/h))

Offline jamespetts gb

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Re: Why is it that older gamesaves don't allow you to buy certain locomotives?
« Reply #18 on: October 20, 2018, 08:56:15 PM »
Okay I understand what you are saying, but my point is that I want to have loco hauled passenger train/freight services using the locomotives and wagons which are too heavy for the 120 km/h (75 mph) track. However, one suggestion that I am putting forward (may need a new topic for this) is to have different types of track with different speed limits (e.g. 26 tonne track with a max. speed of 75 mph (120 km/h) or 22 tonne track with a max. speed of 105 mph (168 km/h))

Is there any evidence that such track existed?

Offline mammothim2906 england

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Re: Why is it that older gamesaves don't allow you to buy certain locomotives?
« Reply #19 on: October 20, 2018, 09:16:26 PM »
Is there any evidence that such track existed?

Not in Simutrans as far as I am aware. But in Transport Fever, there is this track mod which allows you to lay down track with different speed limits

Offline ACarlotti

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Re: Why is it that older gamesaves don't allow you to buy certain locomotives?
« Reply #20 on: October 20, 2018, 09:22:47 PM »
Is there any evidence that such track existed?

I'd have thought that it could be the same track but with different speed restrictions for different types of train. It very common in the UK to have different speed limits for multiple units and other trains (or some other partition of the stock into two groups). I imagine this would be because some stock imparts a lower dynamic load on the track (for a given speed) and can hence be run at a higher speed without damaging the track. The most obvious reasons for this would be either a lower weight (axle weight in particular) or better suspension.

Of course, this is a little different to what is being asked for.

Offline mammothim2906 england

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Re: Why is it that older gamesaves don't allow you to buy certain locomotives?
« Reply #21 on: October 20, 2018, 09:45:23 PM »
I'd have thought that it could be the same track but with different speed restrictions for different types of train. It very common in the UK to have different speed limits for multiple units and other trains (or some other partition of the stock into two groups). I imagine this would be because some stock imparts a lower dynamic load on the track (for a given speed) and can hence be run at a higher speed without damaging the track. The most obvious reasons for this would be either a lower weight (axle weight in particular) or better suspension.

Of course, this is a little different to what is being asked for.

I like what your saying ACarlotti and I would also put this down as a consideration as well
« Last Edit: October 20, 2018, 10:05:52 PM by SouthernTransport225 »

Offline jamespetts gb

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Re: Why is it that older gamesaves don't allow you to buy certain locomotives?
« Reply #22 on: October 20, 2018, 10:16:27 PM »
Not in Simutrans as far as I am aware. But in Transport Fever, there is this track mod which allows you to lay down track with different speed limits

I mean in reality, as the pakset is intended to be based on reality. I would need information about the physical characteristics of the track in question to be able to differentiate it by description of physical characteristics as all of the track in the pakset is currently differentiated.

As to ways with different speed restrictions for different types of vehicles, doing this properly (i.e., with a sufficient level of abstraction to apply everywhere where it might apply in reality, and so that its economic implications were clear to players and realistic) would take a truly enormous amount of work (at least half of which would be very detailed research about why such differential speed limits exist and the economics behind them).

If anyone is volunteering to do all this work, that might be something worth considering.

Offline SuperTimo

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Re: Why is it that older gamesaves don't allow you to buy certain locomotives?
« Reply #23 on: October 22, 2018, 10:32:54 AM »
(at least half of which would be very detailed research about why such differential speed limits exist and the economics behind them).


From my understanding from my work, differential speed limits are usually related to signalling (although there are other cases such as tilting trains on the WCML and some structures). Generally they exist to allow a stock type to use a line for which the signalling has not been designed, or to get a bit more of an advantage out of rolling stock which has better performance than the current system. My experience of working on projects with multiple signalling systems is that differential speeds tend to be far more common in areas with 4 aspect signalling than 2 aspect or absolute block signalling.

Traditionally a line's signalling is designed with the braking distance of the slowest braking rolling stock in mind, which usually will be freight. However on busy commuter lines, such as the Brighton Mainline (BML) freight is relatively rare and designing the signalling to accommodate freight would comprise the headway of the line for little to no benefit. Therefore to enable freight to use the route a differential speed limit is created (BML uses the 2/3rds rule which states that freight trains are permitted at 2/3rd of the linespeed except where a specific differential speed limit applies). This speed limit will be calculated such that the slowest braking speed for any permitted freight consist will allow it to stop within 1 or two signalling sections (depending on the number of aspects that signalling system uses).

The opposite can also be true. In some cases a train may have a slightly better braking characteristics then the rolling stock that the signalling was designed for. As such certain stock types (usually multiple units or HSTs) can be permitted at a speed limit higher than line speed (normally only 10 - 15 Mph higher) in order to achieve slightly improved journey times. Such speed profiles were commonly introduced by BR in the 1980s when HSTs and Sprinter DMUs began operating on lines previously worked by loco hauled trains. In this case it was not economical to upgrade the signalling for the new rolling stock, but journey time improvements could be made by increasing the speed limits for the new stock to operate within the existing system.


This picture shows an example of a differential speed profile with a higher speed for DMUs (albeit with a non-standard sign)

It is possible that some features of the Permanent Way will require a differential speed profile, however from my experience this is not usually due to track curvature and more to do with weak structures. Freight trains exert considerable dynamic loads when travelling at high speeds and as such may be slowed to reduce the wear on certain structures on a route.


For example this extract from the National Electronic Sectional Appendix (this is available publicly by the way) shows the famous Morpeth curve at the top of diagram where the speed limit changes from 110 Mph to 50 Mph. Despite this being one of the sharpest corners on a mainline in the UK there is no differential speed limit as the signalling system can accommodate freight trains at line-speed.

From an in game perspective a lot of this should be represented by the signalling modelled in the game, however a useful feature could be to allow the player to chose a line-speed for a section of line. Often when express trains arrive into termni in cities it could be useful to restrict them to the speed of local trains to prevent them catching up too quickly and therefore constantly stopping and starting when they catch up with a slower train, the same can be true of freight trains when they are behind a stopping service, a lower speed limit for freight could reduce the need for them need to stop completely.

Offline jamespetts gb

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Re: Why is it that older gamesaves don't allow you to buy certain locomotives?
« Reply #24 on: October 22, 2018, 10:41:00 AM »
Thank you - that is very helpful. It is evident that these multiple speed limits are not useful as a property of a type of track, and this functionality is indeed already implemented in the signalling code.

As to speed limits, since there is no actual disadvantage to a player of a train catching up with a slower train in front and then stopping (and this is realistic behaviour, after all), there does not seem to be any functional imperative to implement this feature.