gradients ?

[Mr Snail]

I am in the early stages of planning an OO gauge layout and I am looking for some advice about gradients.

 

 

 

On the layout the passenger station is on top of the hill, on the approach to the station the line diverges at B and crosses under the station at A to access the freight yard and docks. The track distance between A and B is about 95 inches. To fall the necessary 3 inches over this length would give me gradient of about 1 in 31. So this leaves me with two questions I was hoping you guys could help me with.

 

1) Is 3 inches sufficient clearance to go under a bridge?

 

2) Is a 1 in 31 gradient two steep?

[amdaley]

Hi Snail.

1) Is 3 inches sufficient clearance to go under a bridge?

 

Yes 3" is plenty. You can bye with 2 3/4" if its just to pass under a bridge.

 

2) Is a 1 in 31 gradient two steep?

 

I would suggest for comfort should aim for a minimum of 1 in 50. Sometimes it is possible to achieve a better gradient by lowering one track while raising the other.

[Pete Harvey]

Three inches should be enough.

 

I have attached a .pdf document that will give you the scale measurements for what you want to do?

 

civil_eng.pdf

 

Pete

[34theletterbetweenB&D]

For running lines 1 in 31 is rather on the steep side (and by the way the constant gradient section will be steeper than that, you have to allow for transitions on and off gradients) but for a freight line down to the docks, entirely appropriate. Lots of movements bringing small cuts of vehicles up and down will add operational interest. You might even consider a 'low bridge' scenario and have special low cab and boiler fitting locos, and restriction on freight vehicle heights, to add a little twist to operation.

 

 

[Mr Snail]

Hi Snail.

1) Is 3 inches sufficient clearance to go under a bridge?

 

Yes 3" is plenty. You can bye with 2 3/4" if its just to pass under a bridge.

 

2) Is a 1 in 31 gradient two steep?

 

I would suggest for comfort should aim for a minimum of 1 in 50. Sometimes it is possible to achieve a better gradient by lowering one track while raising the other.

 

Thanks for that, I never thought of increasing the height of the station to decrease the drop required. I will play around with the station approach and see what's possible.

 

 

 

Three inches should be enough.

 

I have attached a .pdf document that will give you the scale measurements for what you want to do?

 

civil_eng.pdf

 

Pete

 

That is a great pdf, thanks for sharing

 

 

 

For running lines 1 in 31 is rather on the steep side (and by the way the constant gradient section will be steeper than that, you have to allow for transitions on and off gradients) but for a freight line down to the docks, entirely appropriate. Lots of movements bringing small cuts of vehicles up and down will add operational interest. You might even consider a 'low bridge' scenario and have special low cab and boiler fitting locos, and restriction on freight vehicle heights, to add a little twist to operation.

 

 

 

The layout will be set in the late 80s early 90s.