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“Warming up throughout the day” - a myth?

Nicky Borrill

Strata Poster
There’s a decent documentary on youtube about the construction of Formula Rossa. It explains how hot the wheels get on a rollercoaster and goes on to show that combined with the desert heat in that particular location they would simply melt, so they’ve installed cooling water jets.
 

MestnyiGeroi

Giga Poster
To be fair, I used to think it was bollocks too, just coaster nerds sounding off and trying to come across as the 'expert', but I gotta say I have since experienced it myself. To differing extents and over differing time frames, and I've only noticed it on certain coasters... but it definitely happens.
Some examples:
Icon. The most obvious one. Takes aaaages to 'warm up' properly. Seems to gradually get faster and faster throughout the day. Very noticeable difference between first and last rides.
Nemesis. Delly P will back me up on this one - we had a very early ride one day, 1st or 2nd lap of the day. Sluggish. Then again 10 minutes later, same train, boom - the thing was mental, absolutely flew around the track. Clearly one that 'plateaus' quite quickly.
Saw & The Smiler. Not so much 'gets faster' with these two, more like 'gets rougher', but I suspect they're related. Maybe they get rougher because they get faster? ?
Steel Vengeance. Maybe it was the darkness playing tricks on me, but night rides definitely felt faster. Same with Shambhala.
Don't ask me to explain the science behind any of this - that's Hixee's job - but as a goon with a moderate amount of experience, I can confirm that it's not just a myth.
Examples that first spring to my mind are Nitro and Leviathan — entirely different coasters when fully warmed up.
 

cocoa

Mega Poster
I quite liked your analysis in the first post. There's been a lot of people chiming in with anecdotes which is fine I guess, but doesn't actually address most of the issues brought up, with the exception of Hixee's great response. I suspect we all agree that we've experienced the phenomenon of rides warming up, so the question to address is 'exactly how' or even, to what extent is this something we project onto the rides. As for night rides in particular- I have no doubt at all that decreased visibility massively increases the feeling of speed. I think this is well established- but if we're sticking to anecdotes, I always think of space mountain as a ride that feels way faster than it has any right to. So, we should restrict our question to compare rides in the same level of lighting but ~8 hours apart in the day.

I think I've asked CP6 about this before and I can't remember his exact response but I believe he would have mentioned the wheel grease acting quite differently under 'mild' temperature changes. I am somewhat curious also at the time period it takes to heat up the wheels to their 'equilibrium' temperature profile (where the heat they lose to the environment throughout one ride cycle, including stopping etc, is equal to the heat they gain via friction). I would naively have suspected not that long- surely 5-10 or so cycles would be sufficient? I could absolutely be wrong here but I agree that it seems weird to me that a ride would need to take ~6-8 hours to experience this. I have no engineering experience whatsoever though- perhaps my naivete here is well off the mark and wheels do keep getting hotter very slowly over the course of a day.

The same thing with joints in supports and things like this- I presume rides are not cycling quickly enough to build up any sort of vibrating/resonance effects in the structures, or at least this is something manufacturers would really try and reduce.

I imagine a 10-15 C increase in temperature throughout the day could have important effects, and happen gradually. Although by sunset, usually, the day is noticeably colder than at peak and I'm not sure everyone would agree that rides peak in speed at around 2-3 pm.

So yeah- I'm also a bit curious about the explanation here. I suspect there's a component to what you said about anthropomorphizing the coasters- human experience is such a dumb subjective thing sometimes and this wouldn't crack the top 20 of illusion-y psychological/sociological effects we do to ourselves. But I would also suspect there is some interesting physical mechanism going on here, I'm just not yet 100% convinced by the conventional answers.
 

Nitefly

Hyper Poster
Thanks for the reply @cocoa - seems like we share similar thoughts.

The wheel grease theory is definitely the most plausible but, like you say, I can’t see how it would take hours to have an effect ?

I agree that night rides themselves should pretty much be discounted entirely from the analysis - good point re: space mountain!

We need a ride engineer to give us the low down!! :)
 

bob_3_

Giga Poster
This is a really interesting thing that I thought about before I worked with rides. But honestly from experience and literally sitting at an ops panel monitering how long a ride takes to complete a circuit, this is not a myth at all. Rides definitely run faster in the heat and towards the end of the day.

It also explains why trims are added to a ride as they are there to ensure less wear on the trains and track and the coaster consistently provides the same experience for everyone when the speed varies. The the ride time can vary a lot! Nemesis' lack of trims is great for us, but it causes alot of maintenance issues due to the sheer speed the thing can run at times, and is the reason all modern B&Ms have a form of speed control midway through their rides. Galactica would complete the course around 54 seconds in its morning tests and its first hour of rides with guests, but on a hot day can surpass 50 seconds towards the end of the day. Although "night rides" do give more of an illusion of speed as the low light can make you appear to go faster, a lot of the time if they've been running all day it is running at its fastest at this point. So the combination can make the coaster feel like it's in SUPERSPEED.

Another variant you will have depending on the ride is the weight of the riders, you experience this more on a coaster with lighter trains (B&M trains tend to be heavy enough that ridership makes less difference). Using Alton coasters as an example, Thirteen and The Smiler require special attention when running in the cold and empty as there is a huge risk of valleying due to the lighter trains. Thirteen tackles this by running in a special "no guests" mode with the trims turned off. The Smiler regularly needs waterdummies when the trains first complete the course. You may notice heaters in Galactica's station pointing towards the wheels to help warm them up quicker.

There's also greasing of the track, Galactica has a section the trains run over that is daily covered in new grease, on cold days the grease is more solid and less is added until it warms up.

BASICALLY. It's not a myth, but there are a lot of procedures in place to make sure the variation in speed is kept to a minimum.
 

Hyde

Matt SR
Staff member
Moderator
Social Media Team
I quite liked your analysis in the first post. There's been a lot of people chiming in with anecdotes which is fine I guess, but doesn't actually address most of the issues brought up, with the exception of Hixee's great response. I suspect we all agree that we've experienced the phenomenon of rides warming up, so the question to address is 'exactly how' or even, to what extent is this something we project onto the rides.
...
I am somewhat curious also at the time period it takes to heat up the wheels to their 'equilibrium' temperature profile (where the heat they lose to the environment throughout one ride cycle, including stopping etc, is equal to the heat they gain via friction). I would naively have suspected not that long- surely 5-10 or so cycles would be sufficient? I could absolutely be wrong here but I agree that it seems weird to me that a ride would need to take ~6-8 hours to experience this. I have no engineering experience whatsoever though- perhaps my naivete here is well off the mark and wheels do keep getting hotter very slowly over the course of a day.
The short answer is "it depends". Roller coasters with wider tolerances and bearings (aka wooden coasters) require almost no time at all to "warm up", as these wheels experience far less rolling resistance (all steel, no polyurethane composite), and are able to quickly heat up being all metal. This is especially true for longer roller coasters, as each cycle allows plenty of heat to build up in the wheel assembly, bringing them quickly up to temperature. A good example of this is respective amusement parks operating wooden coasters during December Christmas events - these coasters have a wider set of operating temperature, and are able to cruise through lower temperatures as wheel assembly is less susceptible to fluctuation.

For roller coasters with tight tolerances and clearance of wheel assembly (think modern steel coasters with polyurethane, constant contact of all three wheel assemblies to the track at all time, etc.), these wheel assemblies will experience greater rolling resistance when cold, and require respectively greater time to heat up (going partly into the weeds, these different materials have greater thermal mass, meaning it takes longer to heat up). Length of roller coaster is extremely imperative here as well - even if a roller coaster spikes up to 80+ MPH, unless it's sustaining this speed the entire length of the run, it will indeed take a few cycles to bring the wheel assembly up to operating temperature (e.g. KK or TTD, spiking to 100+ MPH but only lasting 16-20 seconds).

Ambient air and time in station also plays a role into this warm-up process. If it's a colder morning, heat will dissipate more quickly from the wheel assembly, requiring repeated ride cycles to bring the wheel assemblies up to temperature. As ambient air temperature rises however, heat will dissipate less from the wheel assembly, and cooling effect will also be reduced while the coaster is running through the course (aka it's easier to cool something when you're blowing 60F air vs. 90F air). As @Hixee mentioned, this is why some parks employ sprayed water cooling to cool wheel and brake assembly.

There absolutely is a human observation factor that can cloud this whole perspective. But I've been on my fair share of "first ride of a cold morning" vs. "hot afternoon" rides, and it's an extremely well documented effect of rides with warm vs. cold wheel assembly. Specifically, I recall a ride on Outlaw Run that @Hixee, @Snoo, @kimahri, @Youngster Joey, @Error, and I took first thing in the morning, where the train crawled through the final barrel roll. Riding it later in the day, the coaster train was noticeably faster.

[Edit] - Also interested to ask as I personally don't know - is anyone aware of the specific lubrication/grease that is used with the wheel assembly? I'd imagine it's a sealed bearing that shouldn't require new lubrication to be added after manufacturing (makes for farrrrr easier upkeep), but also interested what the exact viscosity rating of this would be - such as how modern gasoline/diesel engines use a 5w20 oil, which operates as a lighter weight when cold, but becomes heavier in operation when hot to protect parts (aka letting the engine warm up more quickly). Super niche question I'd only expect manufacturers/select few to know, but also curious.
 

cocoa

Mega Poster
^great points. I could buy that the combination of very short ride cycles (eg outlaw run), wheel construction/materials, long station/ idle time, and the ambient station temperature slowly rising is responsible for the much longer (~10s to 100s of cycles vs ~few cycles) heating time of the wheels. That would make me guess that a ride with less down time and longer running time shouldn't experience this as much- maybe like Hagrid? versus say an approximately equivalent ultralight or something, which I've heard do seem to warm up. I've only ridden Hagrid once in the morning so can't comment!
 

PeteA

Roller Poster
This is all to do with the oil in the wheel bearings. The very nature of how a bearing works, means that is has to have oil in the wheel assembly otherwise it will fail. Depending on the oil used and the range of temperature that particular lubricant works in, will effect the performance when it hasnt been used for a while, ie overnight.

Simple science experiment to see what I mean, put a bottle of Olive Oil into a fridge overnight and then next morning try and pour it out. As long as your fridge is at 8 degrees or less you will find the oil is solid and has to be warmed up to become liquid.

Its the same principle for coasters (and cars, bikes etc). Depending on the oil used, the friction will be more first thing when it hasnt been used for a while, to something that is constantly in use.

As mentioned before by others, some coasters have cooling mechanisms and some also have heaters, for example Avalanche at BPB always seems to have the heaters on.
 

jay37415

Mega Poster
Maintenance guy here (not amusement park but large factory):

It does have a lot to do with the grease. Obviously the grease in the wheels have a chance to cool down overnight and thicken. It takes some time for the grease in the bearings to warm up to optimal operating temperature and thin out a little so the coasters will pick up speed in the afternoon. As someone stated earlier, there is a plateau in the optimal operating range. Once the grease gets too hot, it will break down and cause the bearings in the wheels to fail.

How often the bearings get greased is mainly determined by manufacture's specifications. Over greasing a bearing is just as bad as under greasing. There is nothing high speed in our factory so we only grease bearings every six months. On the contrary, I remember Steel Phantom at Kennywood having to stop every 4? hours on warm days to have the bearing lubrication checked due to the high speed of the coaster.

If you want more reading on this topic here a nice article:

EDIT: I forgot to mention that many coaster have timers built into the PLC logic for the operators to monitor. Usually from the top of the first drop to the brake run. Had the operators on Storm Chaser tell me that on hot afternoons, the cycle times can get up to 6 seconds faster. So to answer the question... YES coasters do get faster.
 
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FistedColossus

Hyper Poster
Don't know about the science but it's definitely not a myth. I didn't really notice it for years tbf.

Icon is the ultimate example as others have said. First thing in the morning it farts you out of the station and crawls over the top hat. Any time after 2ish it's a different beast, flying over the top hat and giving strong ejector airtime. Personally it's nowhere near my top 20 because a good coaster should deliver in all conditions.

Untamed and Storm chaser are similar but still very good early on.

Steel Vengeance and Taron it's noticeable but they're still world class at any point in the day.
 

Hyde

Matt SR
Staff member
Moderator
Social Media Team
Don't know about the science but it's definitely not a myth. I didn't really notice it for years tbf.

Icon is the ultimate example as others have said. First thing in the morning it farts you out of the station and crawls over the top hat. Any time after 2ish it's a different beast, flying over the top hat and giving strong ejector airtime. Personally it's nowhere near my top 20 because a good coaster should deliver in all conditions.

Untamed and Storm chaser are similar but still very good early on.

Steel Vengeance and Taron it's noticeable but they're still world class at any point in the day.
(I think we covered the science in the 4 previous posts. ;) )
 

JJLehto

Hyper Poster
I dont claim to know the physics and science and nitty gritty detail, but I really gotta go with the observation test on this one.
In the morning rides just aren't quite as fast, and are later in the day. Not just a few times but a lot, over all my years of riding.
There's got to be something to it. It's not always substantial and a good ride is still good, but from small woodies to MForce, RMC's and wing coasters...it's absolutely noticeable and I can't believe it's not happening.
 

Howie

Donkey in a hat
Great topic this, some really interesting posts being made. Good work, team! ?
However, allow me if you will to throw a spanner into the works. Well... not so much a spanner, but another 'variable' into the equation. We've got warm vs cold, right, but what about wet vs dry?
Yeah ok, you could argue that weather conditions are just one of any number of variable factors that can affect the speed, real or perceived, of any individual coaster lap, but a 'wet track' is another of those factors that has a popular conception among enthusiasts of producing a 'faster ride'. This seems to be especially prevalent on wooden coasters.
Is this true? And if so, why? And if it is true, doesn't that kinda go against the warm vs cold argument? Doesn't it stand to reason that wet wheels on a wet track on a wet day will be cooler than dry wheels on a dry track on a dry, sunny day?
What happens when a warmed up coaster on a sunny day suddenly gets drenched by a mighty downpour? Does it speed up even more or does the cooling effect of rain and cloudy skies slow it down again? I mean, logic dictates that the mere physical presence of water droplets in the air and on the track would produce more resistance, more drag on the train. Your car doesn't go faster in the rain, so why would a coaster?
I don't know the answers to to any of these questions, but here are some anecdotal examples of my own.
Wicker Man: I've had several rides on this thing now, in a range of different seats and times of day and yeah, afternoon rides generally seem faster than morning ones and the back is generally better than the front... but the best ride I've ever had on it was a 2nd row ride just after a heavy storm. It was mental! I'm not exaggerating - it had bonkers, ejector airtime all over the place. It was fab! :)

Balder: Had a mid afternoon ride, coaster had 'warmed up', fairly sunny day. It was pretty good. Had another ride a couple of hours later, twilight, air had cooled, light drizzle. It was mental! Bonkers ejector airtime all over the place.
What is going on here?
Look forward to hearing some theories and examples of this one, and whether it reinforces, or contradicts @Nitefly 's original post.
 
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HeartlineCoaster

Theme Park Superhero
^Rollercoasters can run in the rain? :eek:

Alright, serious answer.
Wet surface = less friction?
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Actually, I'm not sure.
I don't think I've ever personally experienced something being faster in the wet. I think there may be more merit to what was said above about the psychological effects of the dark, but when applied to rain. Moving through it can feel faster, plus it's a distraction. You're focusing more on the water tearing into your face, you pay less attention to what's coming next, you brace less for the forces, it kicks your arse more as a result.

I've done many properly soakingly wet laps on things, most recent comes to mind is Troy where I was being waterboarded through my coat. It was hilarious, and amazing, but I never actively thought this was faster, just funnier. It didn't even make it an objectively better ride for me, I'm still eh with it. It was all the other factors that went with it.

I've seen Stealth rollback because of a freak hailstorm, but that's a launch and not retention of speed throughout a layout (well, half a hill), so I don't know if it means anything.


Side thought I just had - the station of Nessie at Hansa - it shows the top speed of the train after each lap.
That's all the science we need right there, let's go watch it for a day.
 
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cocoa

Mega Poster
Surely wet steel has substantially less friction than dry- the extra effect of rain droplets hitting the train car would presumably provide very little extra resistance, compared to the decrease you get from less friction on the rails themselves.

Again, I think we can all agree on the anecdotal/observational evidence- that is presumably not in question. Rides do seem to warm up! We were being good scientists and asking 'why?'.
 

Hyde

Matt SR
Staff member
Moderator
Social Media Team
Side thought I just had - the station of Nessie at Hansa - it shows the top speed of the train after each lap.
That's all the science we need right there, let's go watch it for a day.
Now this is the solution-style thinking I can get behind!

From a sheer physics perspective, rain may actually cause a roller coaster to run less efficient/slower. A couple things to consider:
1. Added moisture in the air (aka rain) creates additional drag - cutting through air is tough enough for a roller coaster train. But adding additional droplets of liquid to smash into the train? This can create additional drag.
2. Wheels, meet water - while initially I'd be inclined to consider how a wet track may provide increased slickness to make wheels spin easier, this may not actually be the case. First of all, these wheels are attached to VERY heavy trains, of which a thin sheen of water will probably not make a difference in how quickly the train wheels can turn. Also consider the number of wheels in contact with the track; a standard steel coaster wheel assembly has 12 wheels per assembly, multiplied by number of rows and +1 additional assembly for a zero car (wooden coasters by comparison will have a single upstop skid or wheel), which can amount to dozens of wheels in contact with the track. Unless there's constant rain, the track can dry out relatively quickly with some many wheels passing over.
3. Rain can bring temperature fluctuation - yes, rain, as a liquid, provides better cooling effect than air, which circles all the way back around to if wheels run better in warmth vs. cold.

One use-case I could imagine having arguable difference: a VERY wet track on a wooden track/old steel coaster with LOTS of airtime, especially for trains with an upstop bar vs. wheel. Since this upstop is a device that implements a lot of friction, having a wet track would lubricate the surface contact between the track and upstop, allowing the train to travel faster through airtime hills. And, since water flows down thanks to gravity, one could imagine a constant rain continuing to pool on the bottom side of the track. Weird hypothetical, but one use-case where wet could help, even if by a fraction of a percent.
 

jay37415

Mega Poster
I don't have all the answers pertaining to water and grease but here's some thoughts.

I think a wet ride would be more noticeably fast on wooden coasters vs steel. If properly maintained. A wood coaster needs the steel rails oiled daily to help reduce friction where the wheel is straining the track. Think the outside rail on a curve or bottom of a drop. Obviously when the oiled sections gets rained on, it becomes very slick reducing friction.
While wood coasters use steel tires to roll on, steel coasters are a little different animal because they will use different compound polyurethane "tires" to roll on. Some coasters will run a softer compound in the cool months and a hard compound in the warm months. I personally do not have the answers as to how those compounds react to the rain.

EDIT: Here's a crazy old school video of the tracks being oiled on Thunderbolt. Skip to the 4:30 mark.

Concerning bearing lubrication, I think it depends on the type of lubrication used in the bearings. Some greases are designed to repel water up to a certain extent where some will not. Water will break down grease to a certain point where a thin grease will have less friction in the bearings. The only time temperature and water become a factor is in freezing temperatures where the water will freeze inside the grease and thicken the bearings.
 
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rob666

Hyper Poster
Big Dipper at Blackpool often stops running in hard rain because they struggle to stop the train at the offload.
Another excuse to run single trains.
 
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