*BUT THEY DID IN POLAR EXPRESS*

Hill: *exists* Thomas had never seen such bullsh*t before

Also worth mentioning, most locos are equipped with reservoirs of sand that is dispensed to the track in front of the driving wheels to improve traction on steep grades or during wet conditions. On steam locomotives this reservoir was on the top of the train in a dome shaped part, known as the “sand dome.”

4:13, There's a slight inaccuracy. Tractive force, in fact, will not remain the same. Tractive force depends on friction, which is directly proportional to the gravitational force applied _perpendicular_ to the surface. While the overall force of gravity will remain the same, when the train climbs an incline, the component of gravity perpendicular to the surface will reduce. For a gradient of theta degrees, the force will now be the cosine theta of what it was previously.

Suddenly Gordon not getting up Gordon’s Hill makes more sense

Canal boats are even worse at climbing hills.

They managed to do a Q&A with James May and keep it at under an hour? Impressive

"trains can't go up hills" Funicular, Incline, Cog, and cable cars: *Am I a joke to you ?*

*has a huge midterm tomorrow* decides to watch why trains can't go uphill

I could listen to James May talk about literally anything for hours and it would be interesting.

Another problem on steep inclines, is keeping the water level constant, especially going downhill. The crown in the firebox needs to be covered at all times. On some downhill runs, the loco has to go in reverse.

Hills: *exist Gordon from Thomas: *sweats nervously

This guy has clearly never heard of the immense power of The Little Engine That Could.

There's something about a British guy talking about trains that makes me feel really nostalgic.

If a train has trouble going up a hill, just call Edward and he'll give you a push

Here in the Appalachians we have a few lines with over 10%, and freight gradients are also 3-5% generally. It just proves the technological marvels that are modern trains.

In Swiss and German Alps there are trains with gear wheels that lock into the gear teeth on the rails. The Train can climb extreme rises.

James May please never go away

Me, who lives on a mountain town and takes the train every day to the university :"really?"

This is a very helpful video for those of you who wonder why Gordon keeps getting stuck on his hill. Now, I know some of you would chalk this up as Gordon being lazy. But even times where Gordon actually tries, he still gets stuck. Now, this can depend on how many passengers ride the Express, the number of coaches Gordon pulls on a daily basis and how quickly he travels with the Express. Considering that the Express coaches are based on the BR MK1 passenger coach, a single one of these coaches can seat 48 passengers. And in the series Gordon is typically seen pulling 5 coaches and one brake coach. So with a packed Express, Gordon would be carrying 240 passengers and their luggage, along with the Guard in the brake coach. A single BR coach weighs 27 long tons, or 60,480 lbs in US terms. And considering that there is a total of six coaches in total on the Express, Gordon would have to be pulling a total of 362,880 lbs or 162 long tons. So yeah, it's no surprise Gordon keeps getting stuck on his hill. He'd have to be moving at a fairly decent speed to make it over his own hill. Take Gordon's his brother, the Flying Scotsman, for example. Scotsman can easily reach 100 mph, and considering that Gordon is an A1 Pacific, it's possible that he is capable of reaching the same speeds. However, the Express does have a speed limit as to how fast it can go. So in order to make it over the hill, without a back engine, like Edward, he'd have to maintain a constant rate of speed without stopping, in order to avoid getting stuck. I'd say something around 60 mph, 75 at most. (Hopefully this provides some insight.)

But what if the train is made out of an Audi S8 and a few caravans?

1:39 That strange face James makes while waiting for his cue.

I knew this already from playing Railroad Tycoon in the 90's. I even knew what the max. gradient would be. It's one of the most important factors when laying track. Funny how that "game" taught me about railroad engineering as well as the stock market, etc.

James: "..if you're a qualified railway engineer." Me: *Smiles happily*

Thomas the tank engine struggled up a hill once. I remember that.

1:39 James trying to read the script

I love how theres a geared logging logo in the video...

This brings me memories of Gordon's hill. That hill in the video makes Gordon's hill look like a nice hill.

At 4:07 the claim is made that on an incline the tractive force remains the same. Actually, it does not. The greater the incline, the less tractive force because the accelerational force of gravity is no longer perpendicular to the track. As an extreme example, at an incline of 90 degrees the tractive force would become zero as the accelerational force of gravity is then moving on a vector that is parallel to the track.

The “tractive” force actually slightly decreases as the train travels up a gradient, it doesn’t remain constant as the video suggested this is because now a component of the trains weight is acting horizontally and thus not proving a downward force into the tracks. It’s only a small fraction however due to the fact the slopes the trains travel up are extremely shallow.

What James forgot to mention is trains do have a system that can blow sand on the rails just in front of the wheels helping with the traction problem.

Actually, they can. It just can’t be more than a 4 or 5% grade or it becomes a issue. For example, Norfolk Southern climbs several tall mountains in Altoona, PA.

"80 degrees" is NOT "80 %." An 80 % grade is one that rises 80 ft for each 100 ft travelled horizontally. An 80 % grade is about 39 degrees.

A couple points of physics not mentioned in the video. A big part of the reason trains aren't good at climbing hills isn't just the traction: it's because, as big as a locomotive is, it's still only a small portion of the weight of the entire train. The vast majority of a train's weight is on the unpowered wheels of the cars, and isn't contributing to its traction at all. Compare this to you: all of your weight is on your feet. All of a 4WD car's weight is on its driven wheels: for a 2WD car this may be more like half of the weight. You may think you're good at climbing hills, but good luck trying to climb an 80% grade while dragging a wagon loaded with half a ton of bricks. And while your car might climb hills nicely on its own, a semi truck or lorry with four fully-loaded trailers (aka a "road train") certainly won't, despite the high grip of the tires. Conversely, a locomotive all by itself probably wouldn't have much trouble with a 2.65% grade.

For something I never gave any thought to, this was very informative.

the little engine that said "the hell with it"

Who just realised trains can’t go uphill? Now when i think of it, thats why they make holes in mountains to go through...

This is why mountain rail lines are impressive. Two that come to mind are the Copper Canyon Line in Mexico and the Hakone Tozan Rail in Japan.

1:00-1:10 the smoke effects are hilarious. He seems like he'd turn nd say "Do you mind?" Lol 🤣

Ah, my first thought is that trains are basically too heavy and it has steel wheels. So, no grip with heavy train and carriages/etc, alongside gravity, will make it struggle to go up vertically at any degrees without it sliding backwards a lot whilst trying to move forwards.

As a swiss train driver, I applaud to your video, and might show it sometimes to people who think that, well, driving a train is probably as easy as being in a car that doesn't need steering, ey? Actually, the biggest economical advantage of the train which is its small friction is also the greatest nightmare for the railway operators. One day, I was driving downwards well below the maximum authorized speed due to bad weather and rail conditions (leaves in autumn). Suddenly, my personal feeling made me think that the train seemed a bit fast, especially in the turnings. So I reduced the effort of the electrical brake and suddenly the speed indicator goes 20 km/h up! Due to the slippery tracks and braking effort, the wheels were actually turning slower than the real speed of the train would have make them do, thus influencing the speed indicator!

As a locomotive Engineer with 25 years experience, I can attest to all of Jame May's talking points. I have run on grades of 3.0 percent and you have to be on your "A Game" for that kind of work. The real issue arises when fuel conservation trumps tractive effort. Fun times.

I was a Locomotive Engineer for a major Railroad C.S.X. and you are right about wet rail or leaves on the rail all slippery conditions but whenever I had slipping wheels or spinning out of control wheels I would use my SANDERS .It helped most of the time NOT ALWAYS but most of the time !

I appreciate the subtle nod to Monty Python’s Flying Circus.

I'll never mock Gordon for needing Edward to go up Gordon's hill again.

For those of you who are confused as to how a locomotive will gain traction in the first place (since like he said steel on steel has little friction), locomtives will use sand to gain a grip on the rails, and as it gains speed, sand is no longer needed. Sand is also used on a locotive's wheels when tackling an incline.

I've been in quite a few trains, long distance travels too... And I literally never realized they never went uphill.. wow.. I didn't even register that was a thing

Us down in nz fixed the problem. They are known as the Fell locomotives and they managed a whopping 6.667% incline known as the Rimutaka Trail.

The breaks have a much larger advantage over the acceleration when it comes to trains as only a few of the many wheels apply power to accelerate, but all the wheels can apply breaking force.

Here in the good old U.S.A., we had a train that climbed a mountain. I rode The Mount Washington Cog Railway to the top of Mount Washington in 1960, and drove an English Ford Cortina GT to the top in 1968. The Cog Railway closed down after a big crash, and the Cortina GT was re-poed.

There is a town in Utah, USA called Helper. This is because the steep climb trains would have to make in the area necessitated “helper” engines to do so.

Small mistake in the video: at 4:07 he says the "tractive force remains the same" on the incline. This is not true. It actually becomes less (making it more challenging for trains to climb hills. In physics terms the force of friction is equal to coefficient of friction (steel on steel) multiplied by the Normal (support force). This Normal force become less on an incline.

You got this big habit of taking something hard to understand and make it easy. Good Job.

There are 2 types of brakes on modern locomotives, the air brakes and the dynamic brakes. Dynamic brakes in simple turn the traction motors into generators. So the locomotives do most the work air brakes are only used if the train starts going to fast.

Definitely recommend taking a trip on the cog railway up Mount Washington. Cool experience!

I honestly think James has all of this knowledge in his head already. I wonder how much research he truly has to do to produce a show like this. Say what you want about his choice of shirt or his lack of forward speed, but this man is a true joy to watch. Especially when it is something he is passionate about.

A few years ago I was going down a 14% grade in the Rocky Mountains and saw a freight train coming up the same grade on the tracks next to the road. If you get out in that part of the world (and I presume in the Alps), you will see lots of trains going up some pretty steep grades.

this is why older roller coasters use something at the top of the hills call anti roll backs, its the same thing that makes that clicking noise when it goes up the chain lift, it stops the train from rolling back

B&O's Cranberry Grade in West Virginia (still used by CSX) has short stretches running about 2.80% and most of it in excess of 2.00%. Helper engines (rear end and more recently DPU) have always been used. For decades, 80 cars seemed to be the magic number for reliable operation, but remote controlled DPU has thrown that out the window. Then there is Saluda Grade on the old Southern. Average grade was 4.24% for about 2.5 miles and there was about 300 feet of track with an astounding 4.90% grade! Going down was as much an adventure as going up. Successor Norfolk Southern took the line out of service in 2001 although to date it is not officially abandoned.

Some trains shoot sand directly in front of the drive wheels to increase traction.

I've heard becoming a locomotive engineer requires lots of training.

things that tries to combat this situation: 1. sanding, basically sprays a sand in between the tires and rails to give a temporary traction (i think it's stupid, not efficient and possibly ruins the metals because it's basically just sanding a metal and slowly disintegrates both the tires and the track) 2. 3rd/middle track with gear (or something idk the name) basically add another rail but the 3rd one is in the middle of the track, and there's also a gear underneath the locomotive that fits onto the track basically the same idea as people taking stairs. 3. this is my idea, why don't they lay a piece of rubber like a very long gum not everywhere but only on the surface area that trains struggle to have traction? doesn't need to be thick and if it disintegrates it can easily be interchangeable

Very well done! Simple but not condescending.

James May: *Sees train at the bottom of a hill * "Does that mean he's not coming on, then?"

What about the Little Engine Who Could?

So I'm commenting on this in 2022, because it was in my recommended, for some reason, and I think people might find it interesting, if anyone sees this. Here in Greece, we have a train called "Οδοντωτός" (pronounced "O-thoh-doe-toss", the "th" as in "the"), literally meaning "he who has teeth". It's called that because the tracks have spikes, or "teeth", sticking out of them , which the train, having the same teeth under the engine and each carriage, grabs onto, to help it move up a very steep incline in it's mountain path. The engine is also rather small, and so are the carriages, so that helps too. It was used in the past to transport people and goods up to a village, from another village lower down the mountain. It was a tourist attraction mainly, pretty much from the get go, when it started working in the 1890's. It's still going today, though there is a modern engine and carriages, but the original engine in is in a museum in the lower village, where the station is.

100% agree having worked for British rail back in the day.

This makes the Little Engine that Could even more epic

Can jeremy drive a train uphill ?? Next time on top gear *Cancelled*

Still love this many years later! Useful every time I play TSW4!

“Why Can’t Trains Go Uphill?” Rack railways: Am I a joke to you?

4:14 With this blow to The Little Engine That Could, my childhood is officially dead.

"Why can't trains go uphill?" Not with that attitude.

I remember learning that the railroad at Walt Disney World’s Magic Kingdom has a slight incline as it approaches Tomorrowland. I was taking the "Behind the Steam" tour and the tour guide pointed out how the train’s wheels were slipping slightly as it went up that incline. It was a very tiny incline (although I can’t remember what it was) but it caused a noticeable problem in three of the four trains in the fleet. Only one of the locomotives could handle it without slipping. I had never thought about this problem before then and now I wonder about it anytime I see a train track in a hilly area.

@0:41 me, screaming at my phone: "percent!!! not degrees!!!"

Does Jeremy know you are out playing on your own?

The point about how little the contact surface of a train to the tracks is, may be one of my favourite facts ever.

i love hearing james may talk about educational subjects. i know clarkson and hammond usually clown him for it, but he’s a very interesting and smart person

An interesting way around this is the tehachapi loop. The tracks go up a mountain a little bit, then level out into a huge loop to let the train build up speed, so they can finish the transit uphill

This makes me appreciate "Gordon's hill" on Thomas the Tank Engine.

Hill:exists Thomas the tank engine:you dare opose me mortal

We all need to appreciate the engineers who made the Snowden Mountain Railway!

Manitou and Pikes Peak cog railway (on the incline of the mountain Pikes Peak, highest rail in the world) is currently being restored and will re-open in 2021! If you ever visit it is a wonderful journey... worth the experience.

The Rimutaka Incline on Wellington New Zealand operated by steam locomotives for 80 odd years on a line with a gradient of 1 in 15. It's amazing how little the engineering enthusiasts of the world know about the little railway. It used a centre raised rail with horizontal cog-like grip wheels to help the locomotives climb the hill on the return journey. The same centre rails were used for supplemental grip on the descent. Look it up!

I was expecting Clarkson to come in the comment section and type "this is the most boring thing on earth after May driving on the track" or something like that

Ah, yes, the area of contact, which is so important in understanding friction. :-P

You're a very good teacher. Keep doing more videos

Technically, the traction force does reduce as the grade increases. (By the cosine of the angle.) It's small at railroad grades, but still there.

The best locomotives for tackling grades are American geared steam locomotives (the Shay, the Heisler and the Climax locomotives). I have heard of a Shay going up a 14% grade before. That's why they were so popular with logging railways. If you haven't heard of aforementioned locomotives, I then suggest you look them up. They're really quite amazing!

I made a 3 year train driver's training but this video taught me much more about traction than my training did.

There is one modern Swedish railway that has some shockingly steep hills for its young age (late 90s/early 00s). Mälarbanan between Arboga and Örebro has hills at 2,5% and allows speeds at 200 km/h, while the normal limit for a new Swedish railway is 1% steep hills.

To go up steep hills, there are special locomotives with wheel-sets having a gear that engages the gear rack fixed to the sleepers.

Reading visual novel about old steam trains, and this information actualy helps me understand the material even more. Thanks. Old steam locomotives are just great beings.

Gordon pulling 1 truck on a level track: "I give up" Thomas pulling 50 trucks loaded with stone, being held back on Gordon's hill: "Little engines can do big things!"

*Nice video. Thanks for Sharing. Love from Vietnam*

Another solution is to spread traction power accross the train. At the German ICE 3 for instance, it can maintain 300 km/h (185 mph) at a gradient up to 4% because of the traction power being divided along the train (it also allows quicker acceleration)

You can use cogs to power the train up steep hills. That's what trains are doing in the alps.

Thanks James, absolutely fascinating. Never knew that!

I love trains. You do a terrific job of presenting the subject in an interesting manner. By the way: Are you related to Queen's Brian May? I gave you a thumbs-up and subscribed. All good wishes!

James May- Trains can’t go up a steep hill. Cog railway train- Hold my beer.