Whats best guidline for pull to weight ratio for locomotives? weight/power/tracteffort whats it all mean?

[C04L]

Good day everyone,
Looking back at the playthroughs i've played I can't help thinking that i've wasted so much time/money into putting too few/much coaches/tanks/box's on my chosen Engine.

It got me thinking so i searched this community but got dazzeled by numbers or just a differant subject. All I want is a simple guildline, rule of thumb, guestimate, of how much tonnage an engine can carry before it starts to loose its top speed. I see the base numbers on the UI of the Engine but I'm not sure on how to tarry those numbers with the weights of whats hauled behind.

Weight, Power, Tractive Effort..... where does it all come together to make sence for a simplton like me.

How do you do it?

Thnks in advance for your guidence.
C04L

[Robbedem]

If you open the details tab of a train, hover over the power rating. (poor, mediocre, good, excellent,...)

It will show you how long it takes for the train to reach top speed on flat, medium and steep sloped track.

[throknor]

Unfortunately, when upgrading a line it won't show you the power rating description, and the best time to tackle this question is when a new engine or train car is available to upgrade a line. So my trick is to (while paused to save money) go to a train depot and create the train I'm thinking of upgrading to and comparing the power rating to the existing ones I have. For instance I've just established that the first tank car upgrade is useless while I'm still using Moguls as I'd have to use less cars to maintain almost the same speed and slightly more capacity. Even more so with the 6-truck passenger cars that only have +2 passengers but weigh a lot more for a speed increase I can't take advantage of yet.

[Buck Fell]

I'm currently playing on a hard, small, hilly map so this question shifts pretty quickly from a ratings comparison exercise to a purely empirical exercise. For instance I have a train moving grain and stone in 1890 with a max speed of 50Km/h that I peg at 12 cars because there's an uphill portion where speed falls off fast with more, that same engine is used for a livestock/food route that is maxed at 7 cars. For that line I just added a second 7 car train rather than doubling the car count.

I basically just kept adding cars till I saw the speed dip down to 22 or so on the uphill portion, it falls off fast after that with extra cars. At 20Km/h every 1Km/h loss is a 5% penalty. Adding an 8th car increases the line capacity by 13 percent but increases the run time by more due to the slower time to top speed down hill and much slower up hill speed.

So on flat maps and even some medium ones the ratings are king but for hilly maps it really depends on the route and steepness. It doesn't do much good to have a 50Km/h top speed when you're spending most of it at 12Km/h.

About the simplest approach is look at the route time, add a car, look at the new route time, if the new percentage increase is only marginally more than then the percent increase in tonnage then add a car, otherwise add a new train.

Side note I'm really enjoying this play through, requires a lot of mixed freight types to be optimal, I use trucks to reach into hard to get to places, let the trains cover the 'flatter' terrain and I'm about to invest in a boat line to move ore to steel since there's no economical train route due to different wagon types for the return trip.

Side note 2, I'd absolutely love some Shay or Climax models for hilly maps that have a top speed of 30 or 40KM/h but a high tractive effort, great for hilly maps.

[ancienthighway]

Power determines how many cars the locomotive can pull, acceleration, and speed when under load.
Tractive effort determines how well it can go up inclines.

I ran a US 0-6-0 with 10 loaded cars. It did fine on the level track, but when it had to climb a hill to that last stop, it slowed to under 8kmph. I later replaced that engine with a Baldwin, which did okay, but still lost speed. Finally the Mogul came along, and the speed lose was minimal.

As far as how many cars, you are limited at first by power, and later by the length of the platforms at the stations. Of course you could just move the station's crossver tracks out beyond what ever overflow you may have running a long train to a short platform.

[Vimpster]

As far as I know there really isn't any rule of thumb. It comes down to looking at the numbers and than experimenting. In some cases a locomotive with higher power and higher tractive effort will perform worse than one with less power and less tractive effort.

Take for instance the Baldwin vs the Mogul. The Mogul has 400kw power and 80kn tractive effort compared to the Baldwin's 284kw power and 70kn tractive effort. If the rest of the train is short enough, and hence light enough, than the Baldwin could still potentially outperform the Mogul because the Mogul weighs 122t vs the Baldwins 50t. If the rest of the train only weighs 50t than you are looking at a total weight of 172t compared to 100t.

These are just the sort of comparisons you have to make when deciding what to go with, along with trying out certain size trains and seeing if they reach speeds you personally consider acceptable.

Also a side note to ancienthighway, tractive effort also effects the initial acceleration of a train from a stopped position. To what extent I do not know.

[C04L]

Thanks for all your comments, you've been really helpful. I understand more about it than before, thanks for your time, much appreaciated

[Tytalus]

Have a look at this thread and associated google sheets.
https://steamcommunity.com/app/446800/discussions/0/215439774872043182/

Devs - it would be really nice if you built a simplified version of this directly into the game.

[Robbedem]

The game (Train Fever, I suspect it's stil lthe same in Transport Fever*) uses a simplified acceleration curve for all trains.
First a train will accelerate at it's maximum acceleration, determined by the traction/mass.
acceleration = traction / mass
(there might be a maximum acceleration too, independant of any other properties, but I haven't seen this)

Very soon however, the acceleration will diminish because of limited power.
The acceleration will be dependend on the power/mass and the speed of the train.
For a flat track:
acceleration = power / ( mass . speed)

So in practice (on a flat track), the acceleration will be the minimum of (traction or power/speed) divided by the mass of the train.
Keep in mind that the speed is in m/s (SI units)

f.e. a train with these properties: 1000kW, 100kN, 200 tonnes
will have it's acceleration decline from 10m/s (=36 km/h)

At that speed, the acceleration is still the maximum : 0,5m/s²
At a speed of 40km/h, that acceleration has dropped to 0,45m/s²
At 80km/h, the train will accelerate at only 0,225m/s²



*Train fever had a braking of 1m/s², while Transport Fever has a braking of 2m/s².
I would have to check to see if the acceleration values are doubled too. (no time today sadly)