Train speed limit downhill

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Thomasviking
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Train speed limit downhill

Post by Thomasviking »

Hi all,

I'm new to this forum, but i've been playing TT fo over 20 years and Open for at least 10.

I've been wondering. I seem to remember the original game did not limit speeds of vehicels downslope, they would just freefall and when level, revert to maximum speed.
However, in Open TTD all vehicles seem to top out at the maximum speed indicated by design.
Is there a way to override this, aka make the vehicles, particularly trains in my case, freefall down a slope?
I usually work with very heavy long trains, and in hilly or mountainous maps.

I checked all use GRF's and none have a speed parameter.
Wagon speed limits are turned off.

Thank you all for reacting.
Eddi
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Re: Train speed limit downhill

Post by Eddi »

i think you were imagining this behaviour... sounds more like a rollercoaster
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Redirect Left
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Re: Train speed limit downhill

Post by Redirect Left »

Out of curiosity i booted up my original Transport Tycoon copy. I can confirm they do not freewheel down slopes.
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jfs
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Re: Train speed limit downhill

Post by jfs »

Trains with insufficient power to reach their max allowed speed on a flat section can definitely gain speed on a downwards slope, though.

You can especially see this if you use the "freighttrains" setting (called "Weight multiplier for freight to simulate heavy trains" in the Settings list). I just tried making a game starting in 1930, where I set that setting to 10, and made a coal train pulled by a Kirby Paul Tank engine. The train can only reach 25 km/h on flat ground, but when it runs downhill it can reach the full 64 km/h the consists allows. After reaching flat ground again, the train starts slowing down because the engine can't provide enough power to keep up the speed against the friction.


skc
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Re: Train speed limit downhill

Post by skc »

As a former, real-world, train driver, I can tell you that NO train driver EVER wants to put their train over the speed limit willingly and regularly unless they want to risk their job or life.
EVERY train driver will observe the speed limit, ESPECIALLY when going down hills, and will do everything reasonable to keep the train under control and below the speed limit.

Real-world railway systems use the weight of the train to determine the braking effort required from the locomotives before the train is permitted to move. If it hasn't got enough braking effort available, it waits until sufficient can be added before leaving the yard.
Similarly, if the train won't have enough power to make it up the 'ruling' grade of a section, it won't get to enter that section until additional power is added (or weight is removed).

There are numerous data loggers employed throughout every railway system, and they ARE checked regularly, and THOROUGHLY so after an incident occurs.
With some trains taking many kilometres (or miles) to stop, it's entirely possible for a minor error by the driver a LONG way back to be the cause.
On approach to long descents, many long freight trains will be doing well below the speed limit, to allow for them to increase speed down the grade and stay below the speed limit.
Thomasviking
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Re: Train speed limit downhill

Post by Thomasviking »

Well.

I guess i remembered wrong. I understand in real life, a train would descend slower than maximum speed in favor of control.
I was hoping to maybe help the trains climbing large mountains a bit more.
I also do experience trains not reaching quoted max speed due to weight, but that wasn't really what i meant though.
I could have sworn i remember trains having overspeed on downhill, guess i'm mistaken.

Thanks anyway!
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jfs
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Re: Train speed limit downhill

Post by jfs »

It can definitely be an advantage to put downhill slopes right after stations, to help trains accelerate out of the station.

If you need to bring them up to a higher level for the destination, you can do that later on the route where it already has the momentum to easily take a hill with little or no loss in speed.
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Emperor Jake
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Re: Train speed limit downhill

Post by Emperor Jake »

The old MiniIN patchpack had a patch that could disable train speed limits, meaning that a train's top speed was only limited by its weight and air resistance. Could be that's what you're remembering?
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