[quote user="upguy42"]
I have to down size my HO train layout. In the past I have had plenty of room, but now my wife and I are building a new house. My train layout room will be considerably smaller. Because of the reduced space I am considering a two deck operation. What is the maiximum grade that would work? My locomotives range in size from small to a 4-8-8-4 Big Boy? Any suggestions would be appreciated.
Thank you for your imput. It is appreciated.
I have a 5-1/2 x 10-1/2 ft HO layout with one end having a lower and upper loop and the main grade on the other end. I cheated some on the crossover clearance (under a bridge) to reduce the grade but still wound up at 2.4%, on about 25"r curve. Most folks recommended trying to stay at 2% or less, with special exceptions.
My locos range from 2-6-0 Mogul to Big Boy (with traction tires). The Bachmann Mogul can only pull about 3-4 cars w/o slipping, may benefit from trying to add weight. My "standard" is an Athearn GP-9, which handles about 10 cars ok (2-1/2 cars per loco axle is my rule of thumb).
Don't forget to allow for vertical transitions at the top & bottom of the grade, which add to the total length needed.
Paul
Modeling HO with a transition era UP bent
I do not have a "Flatland" railway and it does present challenges as I've tried to reduce all grades from 5 and 6% down to 2% as I like to haul 50+ Coal and Oar trains. I've found anything above 2% will cause my heavier and better pullers to bog down and require double headers. I still have one very long curve that's 5% and I will eventually do my best to reduce it to 3% but it won't be easy.
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If one could roll back the hands of time... They would be waiting for the next train into the future. A. H. Francey 1921-2007
There is no simple answer to that question, but in general, try to keep your grades to be no more than 4% (i.e that is 1.2" rising of each 30" long track). This will allow realistic look of the track route and smooth running of the trains.
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Bearing in mind that grades are measured in percentage - number of units of rise in 100 units of run - some prototype standards and examples:
The original transcontinental route UP/CP Omaha-Oakland) was specified not to exceed 2.2% by Congressional edict. That was the maximum grade on the Baltimore and Ohio.
The WP managed to hold their grades to 1%, possible because of the availability of more powerful earth movers and the construction of longer bridges and tunnels.
My prototype, in the area I model, had a sustained 2.5% grade. It was a helper district, even with shorter than average trains. (I use the same standard grade and train length.)
Railroads climbing mountains to reach timber or mineral workings could go to 3%, 3.5% (ATSF Crown King extension, 10 switchbacks included) or higher.
PRR Madison Incline, 5.9%, was operated with special locos that carried extra ballast for adhesion.
The Rio Grande route that is now the Cumbres and Toltec Scenic Railway was built with ruling grades of 1.5% westbound (anticipating shipments of machinery and supplies to the Silverton mining area) and 4% eastbound (expecting mostly empty cars and the occasional shipment of silver to the Denver Mint.) After the mines ran down, a heavy eastbound traffic (oil and agricultural products) developed, and that 4% eastbound from Chama became a royal PITA.
One solution for the long climb to the second deck is to build a train elevator. For HO, a heavy duty steel stud can serve as a car as long as the longest tangent you can fit behind an easily-removed backdrop. A little ingenuity can arrange for auto-stop and for bypass/safety tracks to position themselves when the car is going down (or up) to a different level. (I have a short elevator as part of a loads out/empties in arrangement at my top of the mountain colliery.)
Chuck (Modeling Central Japan in September, 1964 - short trains, steep grades)
upguy42 I have to down size my HO train layout. In the past I have had plenty of room, but now my wife and I are building a new house. My train layout room will be considerably smaller. Because of the reduced space I am considering a two deck operation. What is the maiximum grade that would work? My locomotives range in size from small to a 4-8-8-4 Big Boy? Any suggestions would be appreciated.
There are a lot of other details that need to be known to properly answer the question. i.e. How long your trains are planned to be?, How much drawbar pull your engines have?, How much room you actually have for those grades?, How high the second deck is planned to be?, etc. All of these effect the grades that you can have without a problem. Another thing to consider is to make sure you have enough clearance between the decks for engines and cars for both setting up and rerailing in case of a derailment (as much as we don't like having them, they happen even in the real railroads.).
From my own plans for an expansion (if I ever get the room to do it), I have a small section that I built that goes from flat to about 4" in order to have enough room for a bridge. I found that I had to change the track plan a few different times because I have a loop to get the height I need. The overtrack didn't have enough clearance from the bottom track to allow cars to pass under it. As a result I had to change the grade on the section. I also found that I had to change the way I will run engines on it as well. (I have to turn that small section into a helper district for certain engines due to the power of those engines and the quantity of cars that run on those trains.)