Wet rails reduce friction between wheels and rails

[hasse-swe]

I was at Liseberg in Gothenburg, Sweden before the pandemic when it had rained alot during a short period. As soon it cleared up and the wether radar showed that the rain wether was going away they did not opened all the coasters right away. One of those was "Balder" a intamin wood prefab coaster. When i asked about why they need to wait before they opened it they told me that the rail needed to dry up a bit before opening it.
I asked why and one of the operators (under training) told me that he think it is about that the wet rail reduce the friction between the roadwheel and rails due to aquaplaning.
So it goes "to fast". And there are no trim breakes between the lifthill and final breakerun.
Is it true about that? All other coasters at Liseberg (not "Valkyria", B&M dive coaster and Balder) have block breakes in between start and end.
If it is true, how dangerous could it bee? I think it will be more fun but if it is dangerous i understand that the do like that. This is only Balder that they do like that with.
I thinking on hot days and riding at the end of the day wehn everything is warm and liess friction is the best. So how mutch does water have for an impact on a coaster?

 

[rob666]

They run a little faster, the main issue I think (esp. Big Dipper at Blackpool) is getting the trains to stop quickly coming into the station...steel wheels on wet steel rails don't stop very well.
So BPB often take the Dipper down to one train in heavy rain.

 

[AidanCKY]

They run a little faster, the main issue I think (esp. Big Dipper at Blackpool) is getting the trains to stop quickly coming into the station...steel wheels on wet steel rails don't stop very well.
So BPB often take the Dipper down to one train in heavy rain.

They grease the rails anyway so i'd imagine water is the least of their worries on that one.

 

[The Undead Creature]

Generally speaking, wet rails and wheels make for a much faster ride to the point where it can become dangerous on older coasters that don't have any form of speed monitoring and moderation.
So a ride not being open until it dries out makes sense to me if it has trouble running too fast in the wet.

That said, if the rain comes during the day after the ride has warmed up, it has the opposite effect in that rain will slow trains down for a few laps as it cools the wheels, effectively increasing the friction. This is only temporary though as the temperature reaches an equilibrium and the lubricating effect becomes more prominent and therefore the ride gets a little faster.

I have known really heavy rain to almost stall coasters that were previously running fine because the train has to force its way through the water much like hitting a deep puddle at speed in your car, the braking effect can be considerable even on something weighing 15 tonnes.

They grease the rails anyway so i'd imagine water is the least of their worries on that one.

When you spend a couple of weeks meticulously lubricating your wheels (I rarely ever put oil or grease on the track) and have a nice slick coating that has worked its way around the entire circuit only for the rain to come and wash it all off...... you can't help but look up and huff quitely to yourself then go refill the oil bucket to start all over again.

 

[Lord-Summerisle]

They run a little faster, the main issue I think (esp. Big Dipper at Blackpool) is getting the trains to stop quickly coming into the station...steel wheels on wet steel rails don't stop very well.
So BPB often take the Dipper down to one train in heavy rain.

It's not so much the braking effect of the wheels on the track as coasters free wheel. The braking, on something like Big Dipper comes from the steel fin on the train passing through the brake mounted to the track.
With Dipper there is a check brake as you come onto the brake run to slow the train before it gets to the main hand operated brake section of the station. Rain will reduce the braking efficiency a little so trains will come in to the station brakes hotter. The Check brake can be adjusted to apply more braking force if needed.

Same when I used to operate The Antelope @ Gullivers, the main brake was outside the station in the open, with a single brake in the station. The aim of the operator was to let the main brake slow the train down enough so it would stop in the station brake without overshooting, but releasing the main brake before the train came to a complete stop. when it rained you'd have to wait a little longer before releasing the brake otherwise you risked the train overshooting in the station.

 

[The Undead Creature]

Same when I used to operate The Antelope @ Gullivers, the main brake was outside the station in the open, with a single brake in the station. The aim of the operator was to let the main brake slow the train down enough so it would stop in the station brake without overshooting, but releasing the main brake before the train came to a complete stop. when it rained you'd have to wait a little longer before releasing the brake otherwise you risked the train overshooting in the station.

At what point did we all give up taking the piss out of you for......... "overshooting"....... and leaving the train parked at the bottom of the lift

 

[RevolutionRuleZ]

Wood coasters definitely run better after a rain shower, not really much difference on steel coasters though

 

[Lord-Summerisle]

At what point did we all give up taking the piss out of you for......... "overshooting"....... and leaving the train parked at the bottom of the lift

??
only time i remember it overshooting was during the run up to christmas when the engineer was doing the morning tests and ice in the brakes meant it didn't slow down enough before the station brake, but it was before the ride opened.