Starting Gradients

favorite is to gradually raise the roadbed in a vertical curve, from the flat, to the desired gradient.

In much the same way as transition curves lead from the straight to the required radius.

You don't mention what type of roadbed you are using?

Easiest to get a smooth vertical transition is a plywood roadbed........by cutting out the intended trackbed using a jigsaw, and gradually introducing wood wedges underneath, the ply adopts a natural transition. The trackage will find it easy to follow the gradual increase in gradient of the roadbed.

what needs to be avoided are abrupt changes of gradient........for longer wheelbase stock this can be a reliability nightmare.

This is one reason why the addition of different levels requires far more space than folk imagine.

Hi. Thanks for the thoughts guys. I am building a railway that runs round my full loft, so it is 20' by 12', and on boards of 2' depth. I can't put a diagram up at present, as I haven't got one! I am building it in conjunction with my dad, and he is the design genius! What I have is 2 outside loop lines, that will raise 2" over 10 feet on one side, and 9" on the other (so 1 in 50 and 1 in 45 nominal). The thing is, under the lifted section will be a tunnel section with storage roads, so that will drop 2" from the same point. The two levels will have a gap between them of 4".

In order to build this, I am using MDF as a base board. The slopes will be on straights, so I shouldn't have too much to worry about. I am only looking at running 4 coach trains, or so, so traction is not a huge issue. I have set a test board up, and checked loads at 1 in 40, and it was ok for me.

Oh, and Brian, all this is happening no more than three miles from you!!!!

QUOTE (Robert Stokes @ 20 Jul 2008, 22:30) <{POST_SNAPBACK}>A 2" rise in 10ft is actually 1 in 60. however if you have a bit of transistion top and bottom this will end up with the main part being at about 1 in 50 so that should be O.K. The other side 2" in 9ft averages 1 in 54 so again with transistion the main part will be about 1 in 45.

Hi, for the all important transition between flat and incline I used good old polyfilla over stepped layers of cork to form the very gradual transition to the inclined baseboard. I took some time and care to get it looking just right. At the top I left a bit of the inclined baseboard unsupported and the natural bend of the board from the top of the supported gradient to the flat worked beautifully - probably luck!

It's worth noting that I've found there is great inconsistency between RTR locos on their ability to cope with a challenging incline - my poorest performer in this respect is the Bachmann standard class 4 tank. (Let me know if you want a rundown of how my 20-odd locos perform!)

Cheers Mike

Hi Fireline and welcome to the MRF.

As Alastair says, plywood is probably the best material for constructing gradients, particularly transitions as it adopts a smooth transition line almost by itself. For the transition I work on a rough 'rule of thumb' and actually do a double transition by rising half the mean gradient over the first 300mm and then going to the full gradient over the next 300mm. This spacing is set by my open grid baseboard system.

So if your mean gradient is say 1 in 50, rise by 3mm over the first 300mm and then by 6mm over the next 300mm. Maintain the 6mm per 300mm until you are 600mm from the summit and then reverse the process by rising only 3 mm over the next 300mm. This does mean that the length of your gradient is actually 600mm more than if you drew a straight line between the two points, hence Alastair's comment about gradients taking more space than you may, at first, realise.

Hope this helps,

Expat.

QUOTE (john woodall @ 21 Jul 2008, 14:21) <{POST_SNAPBACK}>A reasonably quick way to get gradients is to use the woodland scenics polystyrene.

These are preformed so really useful.

As a general rule of thumb I have maximum 4% grades on straight track and 2% on curves. If I had more space the layout would have been dead flat, but . . . . . . . . .

John

***John....4% - 1 in 25!! Bloomin heck, a mini funicular indeed - Then again Marklin puling power is legendary, and marklin track is steel or s/steel so not slippery like nickel silver, so you will get away with things Brit modellers cannot. Still, it really steep aint it!

***Fireline????
You have some really good advice already. Best running, best reliability and best "look" on a layout means nothing extreme or sudden. avoiding abrupt changes makes models both look and run better with no exceptions!!

no sudden changes from flat to gradient - always have a transition
no sudden changes from curved to straight - always have a transition
resist cramming track and use largest possible radii curves - always have a transition
use largest possible radii pointwork
no right angle corners in backscenes
no abrupt edges where backscene meets baseboard

BTW, customwood bends as well as ply, so the material is not an issue there.

regards

Richard
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