Trains going underground

[Jochem_LEGO]

Hello, I want to have my trains going underground in My City.

My plans are to make a tunnel that Goes down in the Road. So I do not have it going over my Harbour area

to go Under the table, But do not know what the maximum incline can be. And it this is possible.

other suggestions are welcome too.

[FGMatt]

I think that a generally suggested maximum is one plate in height per track width; but in a layout that size you might struggle with something so restrictive (I'd think you'd want at least 20 plates in height even if using London Underground-style low trains) which would mean an incline taking up the full width of your layout. 

So a good starting place would be to do some testing with the trains that you have in mind to use, and see what sort of inclines they can comfortably handle.

 

The obvious alternative is just to have an underground railway on the level, and adjust parts of the town around it - maybe raising up part of the street level to get the trains under it?

[Kalahari134]

The usual "one plate per track section" advice will be targeted at the lowest common denominator - someone pulling heavy loads with one loco for example. As in real life if you have a high ratio of powered to unpowered bogies you should be able to manage steeper gradients. 

[L-Gauger]

On 9/13/2025 at 4:02 AM, Jochem_LEGO said:

My plans are to make a tunnel that Goes down in the Road. So I do not have it going over my Harbour area

to go Under the table, But do not know what the maximum incline can be. And it this is possible.

 

It depends on what kind of trains you'll be running. 6-wide trains can take steeper grades (generally speaking, not always of course) and often 6-wide trains are a tad shorter than their 8- or 10-wide counterparts, which means less height clearance is necessary. I would do tests with the trains you intend to run, and see what kind of uphill grade your weakest engine + heaviest train will handle. In my own collection I have trains that can't take even a 1-plate-per-track-section grade, and others that have no problem with a 1-brick-per-track-section grade. So your milage is almost guaranteed to vary. 

If, in the absolute worst-case scenario, you find that it's not feasible to go under  the harbor, I have two ideas for what you can do: 

1. Relocate the track to stay off the water.  You might have to move some buildings, but you might just make enough room to put in a small siding or two to make for some operating possibilities. 

2. Keep your track loop where it is, but go up with your grade instead of down. Build a gravel fill or trestle bridge under your track, with a truss bridge at the highest point so it looks as if ships enter and exit the harbor by going under the truss bridge. This might be parts intensive, but the result would be very visually impressive. 

Hope this helps! 

[Narissis]

If you move the road bridge down to align with the harbourfront road in a T-junction, that'd give you additional space for an incline. I think you could then make it fit if it starts right after the curve, especially if you have your trains oriented so they're always going downhill on the steep incline (then you could use a shallower one in the back where you might have the luxury of more space for a gentle uphill return grade).

[faph]

I think this layout would suit a rail bridge like this:

It doesn’t need much hight over the water. Would be a fun play element too!