Ok, stupid question time [;)] On the next to be built stage of my layout, I’m going to have a 4% grade (this is HO btw). All I will be pulling are RD-4 coal hoppers and spine cars (all properly waited). Both trains will both be pulled with a Bachmann Spectrum DASH 8-40C or DASH 8-40CW. What I want to know is if I will need a helper locomotive or not. Most trains will be running at 6-12 cars (all with body mounted KD’s, if it helps). Thanks!
It really depends on the pulling power of the locomotive.
I think the rough approximation is that you should cut the # of possible cars a loco can pull in half for every 2% of grade. So if the dash 8’s can pull 48 cars on straight, level track, you should be OK pulling them up the 4% grade (provided it isn’t on a curve). Now, if they can’t you’ve got to keep adding helpers until you can get over the grade.
On a side note 4% is REALLY REALLY steep. General consensus is keep it 3% or less (even 3% is pushing it), unless it’s a logging railroad or something. I mean, there are a lot of locomotives that have trouble pulling themselves up a grade, much less a string of cars. You should really test out whether the locomotives CAN actually perform as you want them to.
Best way to test them is get a piece or two of flex track, put it on a scrap of wood, do some math to figure out how high you have to raise one end to make the grade 4%, put a loco on the track, and see if it can get up.
If it is going to be built anyway, just wait until done, run a train up the grade and then see if it needs a helper.
I generally use two Union Pacific 8-40 CW Dash units to pull a twelve car coal drag up the really steep grade (not sure what % it is) on my N scale layout without any problems. Of course with the layout being as small as it is (3 1/2 X 6), and being N scale, it fools the eye into thinking it’s a really long train…
Tracklayer
Sensible advice. I’m sure someone could point you to a table or book that has a standard but the only meaniful test will be on your layout. After all there are other factors involved and only a test on your layout will give a definitive answer. For example, on my layout, I have a two track divided mainline. The right handed, uphill route has a slightly gentler grade the the downhill main. I know of several prototype precedents for this. The uphiil grade approximately 1.5 % and I thought that my BLI Mountain could easily pull a 20 car train up it , but after it rounded a curve going up hill, the wheels began slipping. Apparently the curve added drag to the train causing the stall. It means that on long trains, even my 1.5% grade will require helpers. Find out what works and develop your own standards for helpers.
Klicky Mobster
All any of us can do is speak from our own experiences. On my layout(HO), I generally try to limit my trains to around 15 feet. I have a “mountain/canyon area” with about 50 feet of 2.8% grades and several 180 degree turns with a 32 inch minimum radius. I model the Glorieta pass area which actually has more steep gradients than my model railroad. What I have found is that with properly(NMRA) weighted cars and free rolling metal wheels is that 2 of almost any of the good locomotives will pull my trains “up the hill”. All of the above mentioned items will have an effect on your trains’ ability to pull your train. I have also replaced many of my locomotives wheels with solid nickel silver wheels. This also helps their tractive effort. So you will probably just have to wait and see what you can do. By the way, before I switched to command control, I used to run my trains up the hill with 2 Bachmann Spectrum Dash 8 40 C’s. They did fine…
Mikie
If nothing else, adding helpers is operationally interesting.
Yeah, 4% is pretty steep, though.
and the REAL answer to the question:
one (or three) more than you currently have.[swg]
And i mean this in the sense of you can never have enough [;)]
Thank you all for your help! I realize 4% is steep, but its only 4% up and 2% down, so my whole layout isnt 4%. I think I’m going to order two more Dash 8’s from trainworld (only $20) and run a test.
I am facing a similar issue with the planning of my next layout. Space is limited but I have a plan that will allow for a lot of flexability, providing the trains can climb grades near 3.8%(worst case senario). There is a 1% grade path that gets you to and from the same points that the 3.8% path does, but then this is part of the whole operational appeal of the layout.
I have been asking about regearing here and have gotten some good links and replies as to many different ways of increasing the tractive aspect of your loco. Many of which just include ‘tune-ups’ for your engine.