Kerbal MonoRail [ IT WORKS ! ]

[Nazalassa]

Kerbal MonoRail

A bit of backstory:

Spoiler

I remember the first thing I wanted to build in KSP was.. A MonoRail. (no typo)
At this time, I knew almost nothing about the game (it was in January 2017, a long time ago...) -- and so I failed to build a MonoRail (lol).

Then I forgot about it (and about KSP).

When I came back to KSP (two years later) I tried, again, to make one. One more fail.

It is now time for the third try!

I want to do it on Minmus.

LOG:
14 January 2022: Some issues with the monorail test on the Runway. Needs more wheels.

 

________________________________________________________________________________________________________________________________________________

... and then the third try (that used roughly the same technologies as the previous ones) failed and I once again forgot about this MonoRail idea.

As I learnt how to make parts, I decided to create a long rail, to see what I could do on it. Time for...
The Fourth Try!

For ages Kerbals used planes and rockets to cover great distances over land. But none of them could carry much stuff, and there were the occasional crashes and stuff.

So  I  they decided to build a MonoRail system! It would then be used to carry large amounts of fuel, etc., from places where resources are abundant, to places that are the best to launch from.

 

 +-----+
 | LOG |
 +-----+

 [ 220605.1118 ] Test with Ground Anchor. The Ground Anchor seems to be too buggy to be used to tie the rails to the ground. (See log 22.1)
 [ 220606.1239 ] Test for rail attachment. It may be a good idea, but only when no ground is available. (See log 22.2)
 [ 220822.2116 ] Test with a carriage on a rail. The whole thing seems pretty stable, although it isn't (especially in curves). (see log 22.3)
 [ 220822.2232 ] Longer rail and speed test. Prototype can reach 50 m/s, and probably more. Still not stable, due to spring issues. (see log 22.4)
 [ 230202.1854 ] New rail, using a custom 30-meter-long, 1.875m square-sectionned part.
                 Several tests using plane wheels. Still unusable as the springs are either too low to actually do something, or too high and cause the car to derail.
                 New design, using rover wheels this time, as spring set to minimum will not cause some casing collider hit the rail, thus slowing down - and possibly stopping - the vehicle.
                 (see log 23.1)
 [ 230204.1301 ] Test to determine an efficient way of arranging docking ports, to produce as much thrust as possible. (see log 23.2)
 [ 230204.1313 ] Design for fuel wagon and engine, the latter using four of the engine modules previously found. (see log 23.3)
 [ 230204.1341 ] Test of the previously designed vehicles. (see log 23.4)
 [ 230204.1519 ] Test of the cargo wagon and the platform, which allows loading/unloading of vehicles. (see log 23.5)
 [ 230208.1444 ] Stress-tested the chassis: the wheels break often. The issue could be fixed by changing the wheels, though it has yet to be tested. (see log 23.6)
 [ 230208.1542 ] More stress-testing, this time with fuel wagons and in a straight line. Results indicate that more wheels might will be needed. (see log 23.7)
 [ 230214.1831 ] Test for rail segment coupling technology. The technique used works good. It will be kept unless a better one is found (which is very unlikely). (see log 23.8)
 [ 230701.1744 ] A bit of theory about the use of fairings as rails, to make the MonoRail fully stock. (see log 23.9)

TBC

Edited July 1, 2023 by Nazalassa
Log 23.9

[Fletch4]

the problem i see with this is the fact that mminmus isin't in a geosynchronous orbit to kerbin

[Nazalassa]

This will be a monorail on the surface because else you know, KSP physics...
But even with a surface monorail, I'm not sure it'll work unglitchy. Tests with a bridge anchored found out a problem that will probably be unavoidable: Total Build Destruction, in other words the whole thing floating above the ground with all parts disconnected and randomly rotated

.

[Bej Kerman]

32 minutes ago, Nazalassa said:

This will be a monorail on the surface because else you know, KSP physics...

Then it isn't exactly interplanetary. or even interlunar for that matter...

Edited May 29, 2022 by Bej Kerman

[Nazalassa]

Well, by "interplanetary" I meant, "that could theorically work on any planet without significant adaptation of the infrastructures and vehicles" but it was too long

[Bej Kerman]

1 minute ago, Nazalassa said:

Well, by "interplanetary" I meant, "that could theorically work on any planet without significant adaptation of the infrastructures and vehicles" but it was too long

so, a monorail.

Sounds like an interesting project! You think you could beat Stratzenblitz' 40km monorail?

[Nazalassa]

Well, actually... With careful design like he did for his Dres bridge (physics range, etc.) I might be able to, but these tests on Minmus with the Ground Anchor were really disturbing. I got screenshots but I'm too tired right now to upload them.
Good night!

[Bej Kerman]

1 minute ago, Nazalassa said:

Well, actually... With careful design like he did for his Dres bridge (physics range, etc.) I might be able to, but these tests on Minmus with the Ground Anchor were really disturbing. I got screenshots but I'm too tired right now to upload them.
Good night!

Night Night

[Nazalassa]

I think it'll be easier to do a Pol bridge that touches the ground in three or four stations only.

[Nazalassa]

Log 22.1 - Ground Anchor experiment

I went to Minmus and built a small bridge there, on (and attached to) a Ground Anchor to see how it would behave.

After building the bridge, I quicksaved, then reloaded. This is what happened:

Before	After

So, using Ground Anchors for the rail is NO.

Edited February 3, 2023 by Nazalassa
Log 22.1

[Nazalassa]

Log 22.2 - Rail segments attachment idea

I got an idea for a bridge, like Stratzenblitz's Dres bridge: each segment is supported by the segment before it, and -- that's new -- by the segment after it.

The attachment stuff would be like this:

As you can see, the segments are attached using a Mk2 cargo bay on each segment "grappling" 1.25m and .625m fuel tanks on the other segment.

However, this idea is likely to be abandoned, as I don't use Mk2 fuselages (or Mk3, or whatever profile has cargo or payload bays).

Edited February 3, 2023 by Nazalassa
Log 22.2

[Nazalassa]

The project has been currently stopped due to the lack of funds but, don't worry, it'll be back soon!

[Rutabaga22]

3 hours ago, Nazalassa said:

The project has been currently stopped due to the lack of funds but, don't worry, it'll be back soon!

This is in career?! Nice project btw. 

[Nazalassa]

11 hours ago, Rutabaga22 said:

This is in career

Well, in fact it's Sandbox, but I have too many projects to do (TSP, Elcano Challenge, etc.) so I had to stop one of them to concentrate on the other.

The time budget is very limited!

[Nazalassa]

Log 22.3 - Rail and vehicle prototype test

Well, got some time today to think of the monorail.

The best option for tracks seems to be Mk3 fuselages (they are 10m long and are the longest parts in the game with a relatively flat surface). I did some tests:

The vehicles will then be 4m. wide, that's plenty of space for all we need!

Currently doing a more complicated circuit.

 

The vehicle seems quite stable -- it's not (note from future self).

Edited February 3, 2023 by Nazalassa
Log 22.3

[Nazalassa]

Log 22.4 - Longer rail, speed test

Did some tests...

That's the rail.
 

And that's the Monorail, not yet at max speed (which wasn't reached before the end of the rail). It's surprisingly stable.

For propulsion it has a docking port kraken drive.

It is still not that stable, especially in curves.

Edited February 3, 2023 by Nazalassa
Log 22.4

[Nazalassa]

Log 23.1 - New rail and vehicle designs

 

On 8/22/2022 at 10:32 PM, Nazalassa said:

It's surprisingly stable.

Isn't.

I recently got back to those MonoRail things! With plenty of new ideas (and time).

Bill: How long do you want your rail to be?
Bob: Yes

Total length: 2910m. I use a 30-meter-long custom part (I learnt how to do since my previous attempts) with a 1.875m square section. It will be better for stability reasons (everything else that is big enough is more or less round in this game).
 

Test using "normal" wheels. Something is wrong. Very wrong.
 

Spoiler

Veeeeeery wrong.

 

New test, with rover wheels on the sides.
 

... which still doesn't work. It's too, um, bouncy I guess? It's always leaning southwards.
 

After COUNTLESS days of hard research I came up with this new design: entirely with rover wheels. Spring set to min and damper to max.
Cross your fingers.

YES!! It's not leaning!
After all these failed attempts, it seems like I've finally found a reliable design!
And it's fast.
 

Spoiler

And it has a great braking power, too.

 

So, it appears that I can finally make a proper MonoRail in KSP!

I made a test with turns, it seems to work (didn't take any screenshots, sigh). I haven't tested the system with something heavy though... I hope it'll be OK.

 

Spoiler

I think I understood why it worked better with rover wheels: plane wheels have a collider that prevents the wheel from functioning properly when the spring is too low (due to friction etc., the wheel collider goes too high and it's more a landing strut than a wheel); however the rover wheels don't. It means that I can lower their spring values to 0.05 without any issues... And guess what, it all was the spring's fault!

 

TBC

Edited March 5 by Nazalassa
Video goes brrr

[Nazalassa]

Just remade the OP so it's more clear and explains what I'm trying to do in this thread, also I decided to add a log to it.
Also updated the five posts I made to make the whole thing a bit more consistent.

Edited February 3, 2023 by Nazalassa
Updated the posts lol

[Nazalassa]

Log 23.2 - Engine research

Now that I have something that works, I need an engine (a way to produce thrust so that the vehicle can move). I plan to keep using docking port kraken drives.

However there are several ways to arrange them: in the previous tests, each "forward" docking port (the ones to activate to go forwards, so the ones in the back of the subassembly) was only attracted by one "backward" docking port (the ones in the reverse direction), and there were 16 pairs (so 32 docking ports).
But there are other ways to do it! For example, if I put 8 "backward" ports and offset them so that they're all at the same place, and then put one "forward" port just behind them, the "forward" port should be attracted by the eight "backward" ports, right? And if I put not one, but eight "forward" docking ports and offset them at the same spot, that should make 8*8 = 64 "attraction pairs" and so produce 64 times the thrust of ony two docking ports facing each other.

To test it, I made three test ships, each with the same mass but with different docking port configurations. The first only has one docking port on each side [one port is attracted by one], the second has eight "forward" ports and one "backward" [eight ports are each attracted by one], the third has eight "backward" ports and one "forward" [one port is attracted by eight], and the fourth has eight of both (when I say there are eight docking ports, I mean they're offsetted to the exact same location) [eight ports are each attracted by eight].
I then teleported each of these in orbit, fired the kraken drive for five seconds, and measured the change in speed. Here are the results:

Vessel	"attraction pairs"	Velocity change
1	1	53.5 m/s
2	8	55.4 m/s
3	8	55.4 m/s
4	64	444.8 m/s

So it seems that the best thing is eight docking ports on each side (front and back).

Here's the second vessel:

The stack of docking ports are here to make sure each vessel has the same mass.

 

In conclusion: the "eight-eight" docking port arrangement will be used.

Edited March 5 by Nazalassa
Log 23.2

[Nazalassa]

Log 23.3 - Vehicle design

Now that we have the propulsion stuff, it's time to design the vehicles!

The MonoRail needs locomotives, fuel wagons, cargo wagons, and passenger cars (at least). Perhaps ore wagons too, but they are likely to be in the "fuel wagons" category.

So I designed a loco and a fuel wagon: [more pics in the spoiler]

Spoiler

To couple wagons and other vehicles, I use claws, which have the benefit of being easily coupled/decoupled, having a free pivot, etc.
The main drawback, however, is that by default its pivot is locked, and it locks during time warp and when you reload a save. As the "free pivot" thing can't be assigned to an action group, it requires manual toggling on each claw of the vehicle before moving it.

Edited March 5 by Nazalassa

[Nazalassa]

Log 23.4 - Vehicle testing

With a 2910-meter-long rail, I guess I can do a speed test, and see if the vehicle works as intended.

For the first test, I forgot to free the claws' pivots; this is what happened:

So, unless you want to break all of your wheels...

Spoiler

Another one:

With one of the "eight-eight" engine modules (see log 23.2) it can reach more than 50 m/s, with an empty fuel wagon.

Spoiler

But it can't brake apparently

Now, with four of them.

Spoiler

Another broken wheel...

Locomotive speed test: I guess that much speed isn't healthy

That's 602.64 km/h! Better than the TGV

Edited March 6 by Nazalassa

[Nazalassa]

Log 23.5 - More vehicle and platform design

I made a small platform!

Spoiler

Bob was then sent to check if he could board the new cargo wagon. Turned out he could.

Now the MonoRail is at the second platform!
 

Now, a test to see how fast the MonoRail can pass next to the platform without blowing out. Here at nearly 100 m/s.
It worked! (I tried to take a screenshot while it was just next to the platform, but I couldn't)
 

Spoiler

The platfom being at the end of the rail, the MonoRail immediately derailed after that

... and the Mk2 lander can started to spin and well... This happened.

 

So we now have a cargo wagon, a fuel wagon, a locomotive, a rail and a platform. Now the next logival step is -- turns! And then a rail switch, and the KSC overground line 1.

(and a flag too :D)

Edited March 7 by Nazalassa

[Nazalassa]

Log 23.6 - Stress-testing and SPH Line

The tiny wheels I use can surely handle the 5 tons of the loco (or the empty fuel wagon), but can they handle more than that?

Introducing: The temporary-way-too-heavy passenger car!

The 28-ton carriage (still half as heavy as a full fuel wagon) is supported by six wheels and has twelve guidance wheels.
(I also added a bumper with a red light at the end of the track)

To test it I made a line between the runway and the SPH!

Well, plenty of wheels broke :'(
I have to either add more wheels, edit the cfg of the wheels to make them sturdier, or replace them with other wheels.
 

Spoiler

I also added some signals on the side on the line too:

Edited March 6 by Nazalassa

[Nazalassa]

Log 23.7 - Fuel wagon stress-test

The issue was probably that I had a turn in the rail. For a straight line...
Time for more stress-testing.

First try: with 1 full wagon. 74.39 tons on 14 wheels (28 guidance wheels).
 

Seems to work... And it's faster than IRL freight trains (even if it doesn't carry as much fuel as IRL freight trains) lol
 

Second test: now with a whopping 200 tons, on 30 wheels (60 guidance wheels).
 

I'm afraid there are not enough wheels! They're almost all broken and one is even missing (spoiler: I found it later, on the runway).

 

Also you noticed the rail texture change, didn't you? They now use a 10 by 10 (pixels) texture [lol] in the hope of making the game faster.

Edited March 6 by Nazalassa

[Nazalassa]

I think we can all agree that this is ugly.

That's the poor texture:

I really hate Unity image interpolation right now...

Edited March 6 by Nazalassa
The poor texture *sigh*