New Layout - bridge heights?

[Walkingthedog]

First thing you need to consider is will your locos climb the gradient. The very minimum should be 1 in 30. E.g. 30 inches to rise an inch.

[Brian]

In OO the minimum clearance underside of a bridge or any over rail item to the lower tracks rail top is 60mm. Note. all measurements are taken from the lower tracks rail top NOT the baseboard surface. See here for the OO UK structure gauge https://www.brian-lambert.co.uk/Hints-& ... cturegauge
Plus as WTD has pointed out, the very minimum rise is 1 in 30. Examples... for every 1 unit of rise you need 30 of the same units in length. Therefore 1CM rise = 30CM length or 1inch rise = 30 inches of length.

[andruec]

Also curves add implicit resistance so a spiral is harder to climb up than a straight section of track rising at the same rate. There's also an effect (I can't remember the name) that means there is an increased risk of rolling stock being dragged off the inside of a curve.

I do like the layout though, hope you can make it work. And don't be put off - people warned me that my inclines would cause problems and they never have. Too many people are scared of changing elevation I think. It adds a lot to a layout.

[andruec]

Excellent! Level changes make a big difference to a layout.

[Walkingthedog]

Yes they do but you really need to make gradients future proof.

[Steve M]

I hate to be the voice of doom but I fear your design will prove troublesome.

A significant proportion of your inclines are on curves which, has been said before, will increase drag and necessitate even shallower gradients to overcome the drag. Also your inclines start very close to points and with curved track - the transition from level to incline needs to be very gradual or longer locos will spin their wheels as the driving wheels will be lifted from the rails.

You also have a section of incline over another incline making the total height even higher - and by definition that either increases the length of the raised track or steepens the gradient.

[Walkingthedog]

There is no doubt that gradients make a layout more interesting but you need an awful lot of room.

[Steve M]

Yes, I did look - very carefully.

[Walkingthedog]

Don’t forget you’ll need something under the whole length of the track to support it.

[Walkingthedog]

When I added a bridge I measured from the top of the rail to the top of my tallest piece of rolling stock then added a bit for clearance.