Overview
You ever wanted to build your own steam powered locomotive in ME but looking at existing examples just gave you a headache? Well, you’re in the right place then. Here i want to share the knowledge and experience in constructing trains gained throughout 1.5 years of experimenting and testing. After reading it through you should be able to build similar locomotives to those in the pic.
Introduction
Learning on how to build functioning and good looking trains was quite a long process that began in the last days of the year 2018. After the introduction of the propeller nerf (since before that propeller locomotives were a widespread thing), a few people started independently developing wheel based locomotives. After a few published blueprints we decided to stay in touch and share ideas and testing results between each other.
Since then over one and a half year passed and we went through countless iterations of designs, suspensions, transmissions etc. We started our own discord server to share our experience with others and at some point we even learned modding to be able to add our own custom parts designed for usage in trains.
Here i want to share with you most of our knowledge gained during that time, but first and foremost i wanted to thank those three other guys that made creating this possible: Baron-of-Pingas-Bradders, Onca77 and Johnbeere. If you’re interested in learning more, share your creation or have any questions, be welcome to join our already mentioned discord server[discord.gg].
If you’re interested in exploring published designs, there is a collection for locomotives and other rolling stock.
Lastly what i want to show here is the most popular and tested setup. That doesn’t mean others are not possible, they very much are and there are very good designs implementing them. I can only hope you will be encouraged to explore this topic too and find something useful you might want to share one day.
Modlist
As you can imagine there is a ton of mods involved in creating such complicated contraptions. To make everyone’s life easier i have created a modpack containing all the useful mods in its dependencies, so you only need to add this one modpack to your world. I strongly encourage you to subscribe to all the submods on the workshop though, just out of respect for their creators.
[link]
I also encourage you to get at least partially familiar with all the new blocks and their functionality, as that will save you a lot of time in finding small errors or bugs in your builds.
Also due to there being several workshop related bugs it is most recommended to implement bugfixes created by a former ME dev, Deepflame. They are available on his website[deepflame.nl], installation instructions included.
Working Principle
The designs that will be shown here all work on the same principle: a pulling force based on physical wheel-rail interaction where the torque is produced by the steam engine and transferred to the wheels. This is as close to real life trains in both working priciple and the result as possible (with some simplifications) and allows for realistic interactions with the trains concerning grade, freight, wheelslips, etc.
Planning
Planning is everything. There is no point in just slapping together random components and hoping it will work. 95% of time it won’t and fixing a design that has problems is much more time consuming and annoying, than just planning it out beforehand and building it once but properly. Below I will lead you through all the stages of the planning phase I’m used to using myself when trying to design new rolling stock.
Loco Type
The first question you need to ask yourself is what type of locomotive you want to build. There are tradeoffs in everything and it is impossible to build the strongest and fastest loco possible, since it will be stupidly expensive and being huge and unwieldy will fail at both tasks.
A good way to begin is to consider the tasks the loco will be used for.
- How fast?
- How far?
- What freight does it need to carry?
- What is the state of the track?
There is no point in building a 200 km/h (120 mph) loco for player transportation on a short mountain track, as well as there is no point in building a 4000 ton strong loco for pulling few cars of wood from the nearby logging site.
When thinking about that, it is possible to design a loco for more than one task, but always remember that something that is completely universal will be equally bad at all tasks given. Also the more powerful you want the loco to be (and especially powerful and fast at the same time) the bigger, longer and more expensive it will get.
(picture with old transmission from before the pulley mod update)
Width Dilemma. Even or Odd?
You need to choose the width of the frame of your loco. It can either be even or odd blocks wide. Both work and have their pros and cons so the choice is usually depending on what will look better in terms of proportion and decoration possibilities (for example cab width in proportion to the boiler, etc.)
There is a possibility of switching between them in one build using 1×2 catch blocks to offset the grid half a block. But that should be only used in extremely rare situations, as it does worsen the performance by introducing additional grids, which need to be constantly calculated.
Even Designs
Pros:
- Engines line up with the block grid so it’s very easy to decorate
- Timber arches and domes work as they are supposed to
Cons:
- Wheel collisions and grid positions are offset to the side a bit compared to the model
- No possibility of placing 1 wide blocks in the middle
Odd Designs
Pros:
- Wheel collisions and grid positions are exactly on the model allowing for more flush decoration of the wheels
- Various blocks like whistles can be mounted centrally
- Wider axles (5 blocks instead of 4)
Cons:
- Engines are offset horizontally by half a block making it hard to decorate without a lot of drag-placing
- It’s impossible to use timber arches as extensions to the boiler as they simply do not align
- 2×2 blocks cannot be mounted centrally excluding the use of larger smoke stacks, etc.
Basing on experience, odd designs are usually chosen for smaller locomotives, since they have a lot of small parts that should be mounted centrally and this makes it just that much easier. But generally, the even width is what most designs use.
Wheel Size & Arrangement
Before starting your build you need to choose the amount and size of driving wheels that will physically propell your train on the tracks. As most of things to consider when planning there is a trade off between max speed and pulling power.
I recommend using the wheels from the Train Parts Spoked/Full Wheels mods since they were made specifically for trains and align perfectly to the track. There are variants for both even and odd designs.
The size of the wheels is one of the main things differentiating between an express, freight and a switcher loco. Basically the bigger the wheels, the faster and weaker your locomotive will be, but since now gearing was introduced with the pulley mod, a lot more can be achieved and the power/speed much more finely adjusted. Here are the most commonly used sizes for different locomotive types:
Switcher: 2.5, 3.5
Freight: 3.5, 4.5, 5.5
Express: 5.5, 6.5
The bigger sizes can be used too, though it will be increasingly harder to fit withing the height limit of tunnels without having to heighten them manually.
When choosing a size, consider max speed mostly as it will be hard capped by the max engine rpm. More on that in the Pulley Ratios & Max Speed section.
Basically, the more axles you’ll have the more grip you’ll have on the tracks, allowing for less need in weight compensation (see Balancing). Also longer locomotives can be fitted with more engines, giving them more power.
Though the trade off here is that longer locos are much worse at negotiating tighter curves and inclination changes, meaning you’ll need to take much more care and planning when building your track (I may do a tutorial on that too at some point) and your stations and turnouts will need to be longer, etc. It also increases the grid count worsening the game perfomance, which is especially important in multiplayer (see Multiplayer & Grid Desync)
Of course when working on a replica, you don’t have really much choice and both the wheel size and arrangement are given beforehand. You can still tweak the performance a lot though with different pulley sizes and ratios.
Transmission Ratios & Max Speed
Due to the introduction of the pulley mod and the possibility to create different gearing ratios between the engine and drive axles there are now many possibilities of balancing the performance of your chosen locomotive. Just as with wheels sizes tradeoff, there is one here as well. When doubling the transmission ratio, the loco becomes twice as powerful, but its max speed gets halved.
Unfortunately due to game engine restrictions there is an rpm value around the 1400-1600 mark on the engines, above which their movement starts to be erratic and can be described as ‘clanging around’. Because of that, this, together with wheel size and transmission ratio, effectively sets the max speed of the locomotive. Below is a table of max speed values depending on wheel size and transmission ratio in km/h(mph).
The values for the 1:1 ratio (in [] brackets) are purely theoretical and were introduced basing on the other values. The designs with direct transmission usually cap out due to several other reasons and it is very hard to get a wheel based locomotive going faster than 300 km/h (180 mph) due to many other issues that are introduced when travelling at such speeds.
Also please remember that all these values assume the excess of engine power present for the locos/trains mass. If it is underpowered the speed will be obviously lower.
Catch Block Choice
The point of choosing apropriate drive axle catches for your locomotive is important due to coupling height differences and the overall setup of the decoration around the driving wheels. First and foremost two rules:
1. Always use low friction catch blocks
2. Never use the 1×1 or 1×2 type for drive axles
The first rule is pretty obvious, it reduces friction where else power would be lost. The second rule applies to the fact that due their collision setup, those catches start ‘vibrating’ when turning quickly, effectively transforming your design into a slow and jumpy mess. Whenever the lack of offset or the half block offset is needed, just use the 3×3 and 2×2 Offset catch blocks.
What i recommend is using these catch blocks for the following wheel sizes:
2.5: 2×2 Offset
3.5, 5.5, 7.5: 3×3 or 2×2 Offset
4.5, 6.5: 2×2
Now, why is this important? Note that the wheel sizes differ by one full block. That means the axle heights will differ by half a block. That means that the grids of the locomotives will differ by a half block too. Using one set of rules in this case allows for different locos to be compatible with their couplings and floor height. It also allows for an easy overlap of the foot plate over the tender.
Of course nothing bad happens if you do it the other way around, it’s just good to remember that this is a thing when planning (you may have even noticed that the 2.5 size is done the other way around. But that is due to the 2.5 wheels being really tiny and any other usable catches just being too big for the job)
Engine Size & Setup
When making a steam locomotive the engine size and number is mostly dependent on the desired boiler size. In case if other locos it’s how much space there is available to hide the engines in. If there is a choice, always go for the bigger size and advanced type, as much as possible. The larger size is 4 times as powerful as the smaller one and the advanced type is twice as powerful as its normal counterpart.
In usual cases you cannot have too much power but there can be instances of overpowering your engine if you take it to the extreme. It will still work, but much of the engines power will just be wasted due to uncontrollable wheelslip in higher throttle settings.
One final note: due to direct engine->axle pulley transmission being the most effective, you should have at most twice as many axles as you have engines, to avoid powering your axles through other axles.
Guides & Suspension Types
Since the wheels we are using are physical round blocks that just roll on the track surface (which is completely flat and level with the sleepers btw.), you may wonder how our loco will stay on track on curves, since now it would just roll off the track at the first occasion. The answer is Rail Guides.
Rail Guides are small blocks that have the same properties as the Rails Mod bogies (meaning they tend to stick to the track). They are used to guide a piece of rolling stock along the tracks. Before they were introduced, normal bogies were used for guiding resulting in immensely complicated suspension setups like below. Fortunately nowadays all that is done by a single block.
There are two kinds of suspensions used nowadays, depending on the size of the piece.
Single Point Guide Suspension
Very simple and very reliable, used by very short rolling stock. Just a rigid guide in the middle of your locomotive. It being rigid means it doesn’t allow for rotation of the locomotive, it works just like a usual bogie, it just doesn’t float (to allow the loco weight to be on the wheels)
Dual Point Guide Suspension
A bit more complicated but not much. Used for all but the shortest locomotives. It consists of two guides: one being the rotating kind and mounted directly on the frame at one end, and the second one being a rigid one mounted on a catch on the other end. Imagine them being like the bogies of a freight car, aligning the car to the track at two points. The frame mounted one needs to not enforce rotation, since it won’t be always aligned along the track, while the other one is placed on a catch block so it can rotate with the whole grid (so use a rigid one for it not to just tumble around freely)
Here I want to just introduce the two concepts, I will go into more details about them later in the Guide Placement section.
Multiplayer & Grid Desync
Sadly due to the unfinished state of the game there are still many bugs present that need to be circumvented in some ways. While in singleplayer the most that can happen is lag and bad performance, in multiplayer that is another story.
There is an ongoing issue called Grid Desync causing a grid to appear positioned elsewhere than it is in reality (or just vanished altogether) until relog or server restart. This of course renders the whole train unusable.
How to spot grid desync? There are three ways: grids appearing in different places for different players, the fact that you can run straight through the train (the physics are always in the correct position) and the remote ropes appear in a false position.
Grid Desync is depending on many different things and sometimes grids that worked fine just an hour ago, now are suddenly affected. There are though things that can be done to prevent this from happening as much as possible:
- Use as few grids as possible
- Go with an x-4-x or x-6-x wheel arrangement, try to not add bogies if possible
- If possible use just a single engine
- A single point guide suspension is preferred (so short loco length)
- Do not use traditional ‘+’ rope belts for wheel syncing (see Engine Placement & Transmission)
- Do not use nested grids (catch blocks on catch blocks)
- Use single grid cars
Good news is that the block count (as long as it’s the same grid) does not affect desync much at all, so you can pretty much do what you want (but of course don’t take it to the extreme).
Building & Building Techniques
With all things planned out, now it’s time to start building your future locomotive. But first, let’s set up some space and discuss some important things.
Choose your environment wisely. If you have access to creative mode, use it to build your loco underground (F7 to center spectator, F8 to switch to spectator, move underground, Ctrl+Space to teleport character there, F6 to go back to character). This allows for very easy building since everything is static an aligned.
If creative is not possible due to playing on a server, etc. it is good to set up a workstation similar to the one below, consisting of means of accessing the upper and lower parts of the build. It’s also good to keep the build attached to the ground as long as possible (careful to not create dead grids though, more on that later).
There is an undocumented feature in Medieval Engineers that allows for compounding small grid blocks in one position as long as their collisions don’t overlap (to see collisions, go to Shift+F12 and check the Draw Physics box). The trick is to make the game think that the placed block is a part of a new grid while still being perfectly aligned with the main grid, resulting in a connection after placement. There are 3 ways of achieving that, two of which are legitimately doable in survival:
Drag-Placing
Drag-placing is a method used with the mass placing blocks feature of ME: place a small block, hold and drag it out in a line (or add Shift for a plane). All the blocks added after the initial block will be able to compound.
Scroll-Placing
Scroll placing takes advantage of the ability to change the placement radius of the player with Ctrl+Scroll. The idea is to ‘pull’ a to-be-placed block so close to the player that it is not placed on a side of a block, but is instead placed in mid-air, while still being aligned to the build grid. That alignment can be sometimes tricky though and depends on the surroundings of the site.
Wall-Placing
The third way to do this is to place the blocks desired to be compounded on a side of a large block cube or wall, every block aiming at the cube and not the other small grid block. Then just remove the stone cube and copy paste that compounded part over onto your build. This method is especially useful for repeating block groups like windows, etc. which would otherwise take much longer to be compounded block by block.
Each of these is best for different situations and when you start using them, you’ll quickly get a feel which one is the best for the task.
Unfortunately there are several bugs that a builder can encounter, but there are ways to avoid them completely.
Catch Block Crash
The most common and annoying bug when working with catch blocks. It causes a crash if you place something on a sub part of a 1×1 or 3×3 catch that can try to connect to the parent grid. Best way to deal with it is to either use other catches whenever possible, rotate the subgrid before placement considerably or proceed with utmost care, knowing the mount points of blocks, to not allow them to meet.
Dead Grid Bug
The dead grid bug happens sometimes when splitting one grid into two. Sometimes one of the parts (usually the one not containing the ‘root’ block) turns ‘dead’. Meaning it cannot be aimed at for copying or picking up the blocks in survival (although removing blocks with right click in creative still works). In survival it cannot be removed and any block added to it will be ‘dead’ too.
A grid that turned ‘dead’ is unrecoverable (as of todays knowledge) and unless a backup is present, it has to be rebuilt. How to prevent it? When working with a grid attached to the ground, remove the attaching piece first and try to not have to split grids in two parts when working.
As with almost everything computer and data related: backups, backups and even more backups. When building something, take frequent backup blueprints or just copy-paste it next to the previous iteration. That allows both for quick backups when missclicking something (for example removing an engine from an almost built loco) or branching out to test different options.
Frame & Wheels
The best point to start is the frame. If the frame doesn’t work, nothing works. The best setup is having a one block space between the wheels and catches. It allows for some flexibility in the axles and also better angles for the belts.
Important: due to a bug in game, placing the pulley blocks underground will result in permanent corruption of the grid and make it unusable. Therefore they should be placed overground when the rest of the design is already finished. It is also important to not make them connect two grids when placed (a redundant connection should be made beforehand)
Guide Placement
Now it’s time to set up the rail guides. Depending on the chosen method either place a rigid guide in the center (or as close to the center as possible) or go with the dual guide method. I will show the latter since the former is rather self explanatory.
To simulate the behaviour of a real locomotive, the pivot points should be as close to the first and last driving axle as possible. As mentioned before, place the rotating guide on the frame itself and the rigid guide on a catch block on the other side. Note that the guides have grooves on the top side which should be aligned along the track.
For now leave it at that, though remember to leave some space around the existing guides to either add more rotating guides or add a weight jar to the rigid guide in the balancing phase.
Initial Testing
Now that the frame is ready, it’s time to paste it onto the track and see if everything is fine. Just put it there and push it around a curve to look if it articulates properly or if there are any other problems. It may slightly rock due to it being very light, but that will be fixed later.
Of course if you’re working in survival, skip this step since you don’t want to be detaching your loco yet.
Engine Placement & Transmission
It’s time to place the engines in the desired place. Remember to use centered engines if using an odd grid. After that place the smallest pulleys onto the rotors. Note that the pulleys are directional and have a metal plate on one side. It’s good to place all those plates in one direction to avoid having problems with the transmission getting stuck later.
The transmission can be created in many ways but there are really only two rules you should remember:
1. Try to not leave axles not connected to any engines
2. Make sure to have all the axles connected to each other so, that no independent movement is possible.
If you plan on using the loco in multiplayer, please skip to the next segment. If not, you may want to add traditional rope belts between the wheels to ensure better power transfer and to make the wheels stay aligned (they will rotate differently when only connected via the pulleys, which does not look good in case of steam locomotives).
To do that efficiently, split the belts in half between the two sides. Top and bottom on one side and left and right on the other. Also, chains should be used instead of ropes for heavier designs as with the huge forces involved vanilla ropes might tear, even with the Stronger Ropes Mod.
Initial Balancing
The process of balancing consists of finding the right proportions between four things:
- Wheel friction
- Number of frame guides
- Weight on the frame
- Weight on the sub grid guide
Wheel Friction
The wheel friction is the easiest, since for the great majority of designs the value of x3 is right. Sometimes if wheels slip is really uncontrollable x6 may be better. Never go above x10 though as with increasing the friction, the ability to negotiate curves and switches decreases drastically. On curves the wheels being stiffly mounted to the frame need to slip sideways a bit. Adding too much friction prevents that.
Frame Guides and Weight
The guides, just like bogies become stronger with the weight added to their grid. That includes the ‘track attraction’ downwards force, effectively allowing for the wheels to be ‘pushed’ down onto the track by the frame guide. Now each guide calculates the weight separately meaning that if you have 2 guides with 10 weights it effectively works like one guide with 20 weights. Increasing the guide number allows to multiply the force while not weighting the loco down drastically. And you need to add only as many weights as necessary since each added weight subtracts a bit of performance.
Sub Grid Guide Weights
The other guide needs to be weighted too, though not as much as the other one since it’s function is mainly to keep the back (or front) of the loco aligned on track. The best way of doing that is to add a jar or similar container to it and place the weights inside. On larger locos it needs 15-20 weights and placing all of them physically on the grid would take a lot of space and be very hard to hide.
On the example loco here i decided to go with 3x friction, 2 frame guides, 12 weights and 10 subgrid weights. I cannot tell you the exact and ideal amounts for every case, as it will be different for every loco you build. It’s just trial and error really and looking which combination performs best. Which brings us to the next section:
Power Testing
Since the balancing process is essentially trial and error, it needs to be tested and tweaked repeateadly, both with and without load. Since now the loco is able to drive itself and pull loads, i called it power testing.
Play around with the different parameters in the same testing conditions and see what works better. The initial values i guessed worked pretty well and my test prototype was able to achieve max speed of 145 km/h before clanging out, which is almost exactly right on the specification for 4.5 wheels and 2:1 ratio (140 km/h).
Decorating
When you got a working prototype you can start decorating and shaping the locomotive using all the parts added by the mods. It’s good to check the performance occasionally to see if added parts do not interfere with the functionality.
When adding bogies, leading or trailing wheels, etc. the best way is to just place them independently and connect them to the loco with rope from both sides, essentially using them as separate cars connected to the loco permanently. They are no longer needed for stabilisation and this is the most performance friendly way of attaching them whilst still leaving them enough movement freedom.
Final Balancing & Testing
When all the shaping and decorating is done, a lot of mass has been added to the loco in various places, meaning that a second balancing and testing session is needed. Usually though the changes are very minimal if any at all.
Also now its time to fully test the performance on various inclinations, with various loads, etc. By keeping it underground all the time you can still easily change the transmission ratio or other parameters if needed.
Painting
Now is the time to paint your loco and finish the design. You might ask “Why so late? Why not paint it during construction?”
Well, that is possible too. I just found that it is much less work to paint a finished design and it is much easier to see the effect of painting when the thing is done. When painting during assembly, you may have to paint the same block a few times due to mistakes or changes in the construction. It’s just a waste of time.
A second tip i can give, is to first base-paint the whole design white and add colors afterwards. Why? When accidentally misclicking you just remove the base paint instead of the whole paint added. It’s also good to plan the decoration with the painting mechanic in mind (the fact that it paints only whole blocks at once), to be able to add small details in time.
Tenders and Rail Cars
Now that you have a loco ready, it’s time to build a tender or other rail cars. Just as with guides, there are two main ways of doing that:
Single Bogie Cars:
It doesn’t get simpler than that. Place one bogie in the middle of the car, done.
Double Bogie Cars:
To get realistic behaviour with double bogie cars and have them behave good with heavier loads, the setup is a bit more complicated (but still not hard).The idea is to have one rotating, floating guide placed over one of the bogies and have both bogies attached by backwards catches (so that the car frame is their sub grid). Why? Because catches get stronger with increasing mass of their sub grid, so with them being set up that way they naturally adjust their strength to the freight loaded onto the car. The floating guide on the other hand provides stability and prevents the car from sinking.
You may wonder how to get the catches to mount backwards. It’s really quite easy: offset the grid by another catch placed normally and then place the reverse catch using the sub grid of the ‘helping’ catch, which then gets removed afterward.
Congratulations!! You may have now created your first working train. I hope it performs well and encourages you to dive deeper into the topic and continue testing and development yourself.
Thank you for reading and staying till the end. Have fun!