Please bear with me as I explain this. My layout is shaped like the letter " E “, with the back of the “E” against the wall and is 25’ long. I would like to model the Quarry that is currently appearing in MRR. The elevation I am planing at the center of the back of the “E” is 12”, and a length of approx. 4’ for the Quarry. that will leave me approx. 10’ in either direction till I reach the end of the “E”. What is a reasonable decline I can have in the elevation when I reach the end of the 10’ in either direction. As in the MRR Quarry series I will be running a track above the Quarry. What height can I expect to be at when I reach the end of the “E” to begin the turn onto the legs of the “E” that juts out at either end, so I can have the track do the return trip at ground level. Thanks for any input and advice you can give me.
I am in the process of trying to figure out how to configure a new layout. I had hoped to be able to have one track pass over the other, but it doesn’t look too promising at the moment. I am working with a much smaller space than you are.
A 2% grade for “normal” operations seems to be the steepest recommended. Logging and other special cases have steeper. This means that for every 100" of distance you gain/drop 2". For rough figuring you can think 2" over the length of a piece of 8’ plywood (96"). In your 10’ (120") you would drop 2.4", not quite enough for a train to pass over another. Also remember, you do not go all the way to the outside ot the surface measurement and curves change distances.
Hope this helps.
Good luck,
Richard
If I understand correctly you want to go from a track elrvation of 12" to 0". That is a very big change. A 1% grade would drop 1" for each 100" of length. 2% would need 50". Above 2% you are goimg to have some problems. 12" rise is going to need 12 x 50" .which is 600" or 50’. Doesn’t sound doable to me.
What is reasonable depends whether this track is a main track or a spur serving the quarry.
Grade (change in elevation) is normally expressed in %, how much rise in how much run. If I have the track change elevation 2" in 100" of run then that’s a 2% grade. Since 8 ft is 96", its often handy to figure out how much rise you will have in 8 ft.
Normally the rule of thumb is not to have more than 2% on a main track. Industry track, where it will be just an engine and a small cut of cars, can be steeper, 4% or so.
So if you are trying to burn off 12", at 2% that will take you 600" or 50 feet of run.
A common mistake many modelers make is think of their layout as being on a “tabletop” that is inviolate, that everything must go up from that surface. One option whould be to put the quarry or part of the quarry below the “tabletop”. After all, a quarry is a big hole. So now a train going behind the quarry only has to go up 6", or about 25 ft of run.
My initial thought is to rethink the direction of your design.
don’t forget the space required by easements. The length of an easement is about a carlength for every percent of change of grade. And you need two of them, at the bottom and the top of a grade; together they’ll take quite some length.
Paul
All excellent advice. You can’t just ‘barge into’ a steep grade, even if your locomotive can handle the towing part for the trailing tonnage needed to rise out of the quarry, or to climb up to an open pit’s edge, or whatever. There has to be a slight curve at the bottom where it goes from level to grade, and then at the top it must be reversed. Those two vertical easings into the grade, and out of it, cost room.
What lies between the two vertical curves now has to make up for the rest of the elevation change that they can’t achieve on their own! Translated - your real grade will be even steeper than you thought.
The fact is that often small industrial tracks have very steep grades out of necessity. They even employ special engines for that purpose. You should really figure out how to make this all work if you are really keen on this plan. Maybe use two engines, just as the real railroads do when it counts. But, as a general rule, grades steeper than about 3% require heavy and powerful locomtives to earn money. Once you get into the 4-6% range, you need to double or use extra heavy engine, such as tank engines, or geared engines with lots of traction like the Heislers, Climaxes, and Shays. Even so, in our scale worlds, those engines aren’t miracle workers. If a grade is deemed to be very steep in the 1:1 world, it scales precisely for our models as well, but still at the same grade and just as steep. A hard 5% grade for the Kettle Valley Railway is the same as a 5% HO grade.
One thing you can do is try to split the difference. Where things really need to work, but a single grade is just asking too much for your rolling stock, maybe have the ramp up relieved by dropping the area to be reached…split the difference.
Crandell
Note that there are a number of things that are extremely atypical about that project compared to the real world. The tunnel through the rock wall to deliver gravel with a track above is just one, though perhaps the most implausible. The stubby switchback tail is another. The construction techniques are great, the overall concept is … well … unusual at best.
Just because something is published does not mean that it is a good practice. They squeezed that scene into an odd spot with some unusual choices. If you are designing a quarry scene from scratch you can be free to do it more rationally, which will remove the need for the extreme elevation difference.
Even in the space they had, the scene could have been done much more plausibly, with only trucks from the unseen quarry imagined to be in the aisle dumping into a pit on the visible layout to be conveyed into the loading bins over the track.
Byron
Byron,
Thank you for pointing out those items. I was wondering what an expert’s take on that scene would be. I saw the conveyor heading into the bluff just behind the loader and said …Whaaaa…? Also noticed the short switchback tail. The execution of the scene was very well done but the overall design seemed odd. Glad to see an expert confirm what I thought.
OP: One of the steepest grades around, 7%, is in Madison Indiana. It was used by the Pennsy for accessing the Ohio river-front from the bluff’s above. They used 2 heavily ballasted SD9’s. Very short trains. Not a quarry, but the situation might give you some ideas. You can google Madison Indiana ra