Tunnel

[Anonymous]

Hi! I am new to this Garden Railway and I have my stakes all laid out where I will lay my track,I have a stone wall that i want to put a tunnel in, the yard behind the stone wall is higher and where I will come out of the wall will be 28" higher than the lower yard,I plan on building a trestle to bring it back down to the lower level,can anyone tell me how long I will have to make the trestle,I will not be running the train up from the lower yard to the tunnel. Also I will be running the train in front of my waterfall so I want to build a flat bridge across with no structure except a small railing,it will be approximately 9-10' long.

A newbie
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[ndbprr]

In an answer - no. as I understand what you are saying you will only be going downgrade on the trestle and never up so it can be steeper than if you were going to go upgrade on it. Two factors will influence the grade. One is the factor of adhesion of the engines so they don't slide down the hill gaining speed like a runaway tobogan. You should be able to place an engine on a piece of track and determine at what steepness this occurs. I would the use half that grade maximum because the cars behind it are going to compound the tendency from the weight they will add. the second factor will be the transition from flat into the grade. You will need to do that slowly at both ends so the equipment doesn't bottom out or affect tracking. With LGB you could use one of their rack engines in which case you can go quite steeply once you make the transition as there is a geared rack in the center. You didn't say but I would sure avoid a curve in the tunnel also. That could be a nightmare to retrieve rolling stock that derailed. I would also recommend you make the bridge at the aterfall from a box girder rather than a solid piece of wood. It is far stronger. Particularly for that length of a bridge and won't sag as readily. A box gider is just 1" x whatever width nailed, screwed or glued to make a box. You can use 1x2 for the vertical edges and 1x4,6,8,0r 10" for the surfaces. Just make sure youe put the top and bottom piece on the outside and the edges in the center so the big pieces are in compression and stretching. You'll be able to stand on it it will be so strong. With the water nearby you might want to use cedar.

[Anonymous]

Hi! Thank you, I have since talked to someone and they sugested bulding a berm to cut down on the grade and I think I will be able to do it without too much trouble, what i am faced with now is alot of big roots when I am digging out for the bed. I have a few big maple tress close by and they have big roots, i don't want to cut them so i will just dig around them and leave then where they lie,I have dug up about forty feet where my track will be (My poor acheing back but I think it will be worth it when I can sit back and have a glass of wine and watch what i have accompilshed)
I thank you again and if you think I should know about some other things feel free to do so.

[ndbprr]

I would cut out the roots. Over time they are going to get bigger and eventually upset your roadbed. Ever see a crooked sidewalk? 99 out of 100 times it is caused by tree roots. Maples are hearty and it won't kill the tree. Better to put the time on now rather thanhave to tear it up and do it later.