On 2% with 1 unit pulling 12 cars, we started to get wheel slip. We added another unit and pulled about 15 cars fine. I would guess 8-10 cars on a 3% might slip. Our units were milled quite a bit for DCC and Ditch Lights, so may have been running light. -Robert
Right now, I have a 4% ruling grade, and an 'easement' of sorts of 2% for 8". I'm not crazy abour a 4% grade, but to clear doublestacks, and a bridge of some sort, I need about 1 7/8" height. I would like to drop it to a 3% if possible. I may totally scrap doublestacks altogether, and use my original 2% plan.
On many eastern roads, due to low tunnels, the well cars are limited to 1 container, no stack. -Robert
I would push for the 2%. The Gundersons are heavier cars and it is going to require some motive power to pull a train of any length up the 2%. I think if you go above 2%, you will really restrict your operating potential.. Question, can you go with a different track plan,hidden loop back or even a helix to help you gain height at a minimum of a grade? Rob
A helix? On a 2x4'? It would have to be at a 5" rad to fit... The inner curves are at 8" rad already down from my 9" min. I REALLY like your plan on restricting doublestacks to a single stack... That, combined with 'restrictive tunnels' are prototypical, and my grade can be reduced! Cool! How much height clearance should I have for autoracks? I want a 'rack train someday, and I don't want to be restricted for them, too. I have 4 units. This is a mountain layout, doubleheading is the rule. I only have 2 sidings, anyways. I don't think that would be a problem, if a grade required it. A 2% grade, starting just beyond the lower siding would give me 6 feet of run before the upper level overpass. I'm guessing that will give me about 1.5" of height at a 2% steady grade. I measured it, using the cork I plan on using..... I have 1/32" of clearance with full doublstacks, using the 1.5" elevation... A little tweaking, and I should be able to clear stacks with no problems. What do ya'll think?
They don't cross over each other under the mountain anymore, that's the biggest change, and one siding in the upper let is axed. Versus:
It looks like going upgrade from the top right side of the layout, you can get 80" in, and with a 1.5" rise in grade you are looking at 2.4% grade. You can fit double stacks with that 1.5" for sure: -Robert
2.4% will work, but so will 2.2%, or 2.0%... I made some quick calculations... If a 4' slope at 2% is 1 inch, half of that is a half-inch, right? An extra 6" woudl give me a small cushion of height. Sounds good to me! Hmm.. Soldier Summit has a 2.4% grade.....I have a 2% grade cut from foam for 4'.. All I'd need was an additional 2.5' of 2%, and that will give me my 1.5" easy. BTW, I cut my slopes using a bread knife on 2x4'x1" foam, using a door as a straightedge. Nothing too scientific.
Another thing to consider is that you don't have to make your layout 2'x4', you can make it 3'x4' L shaped, or any of a bunch of other small sizes that you can fit in a closet easily. What i would like to recommend, it that you build a cover for your layout at the same time as you build your board, before getting the track down. Why? well it is much easier at this stage of the game to prevent any damage, and a cover makes the whole layout shipable, storeable, and portable without damage. I have covers for my end modules, and I can stack them without worry of damage, so I plan on making covers for my other two modules, but it will be harder now since I have scenery down. Really, you should consider the cover. -Robert
What kind of cover? The reason I'm shooting for 2x4' is compactness. Also, I have the foam cut already...
Randy: Regarding your "how we do it"...pulling long coal drags on 8 and 9 inch radius track...well, here a photo from a show we did in Galveston, Texas: http://www.members.aol.com/zbendtrack/2003_Galveston/Chad_Brian_50plus_Coal_Train.jpg That's an off-the-shelf MTL F7 and 50 PenZee coal cars behind it. It ran for hours and hours, as it usually does. It takes two GP35's to pull it on the same layout. Repeat after me...transition curves, transition curves...<smile> Regards, Bill K.
Bill, When you say transition curves, do you mean easements? I don't see easements there, just standard 9" & 10" radius curves (or is it 8" and 9"). Do you have a slight easement hidden in there? Randy
Randy: Gumble, stumble, (%&$(#) feeble brain cells. Easements. Yes, easements. Sorry, wrong word on the previous post. We still don't own any metric rulers, so we use 8.5 and 9.5 inch radius curves with easements. Those radii are just slightly wider than Marklin sectional track standards. With the easements, that puts the centerline of the track at the required 9 and 10 inch points from the center of the module interface. The first end modules used 9 and 10 inch constant radius curves coming right off straight track. I have no idea how far down in the city dump you would have to dig to find them today. [frown] If you download Atlas's free Right Track Software, you'll find the digital file of our end modules on the Z-Bend Track Yahoo group's file section. We print it out 1:1 size, then use a vibrating engraving tool to put "dots" through the paper into the plywood top. That gives us a great track centerline to work with (cork and flex track). Hope this gives you some ideas. Bill K. Houston
The easement track is only about 4 inches long between the fixed radius curve and the straight track on the ZBT end modules. You'll see it right away on the Atlas software screen if you look at the end module file I posted. That section of track is absolutely straight at one end, and a constant radius curve at the other. And a log-based curve in between those two point. It doesn't take much to "ease" a truck into the curve. The "bent stick" method would work just as well, if software isn't your thing. "S" curves are considered by many modelers to also be fatal, unless there is at least one car length of straight track between the two opposing constant-radius curves. One of the ZBT groups in the northest mandates it. However, consider two back-to-back easements and I think you'll find it takes far less (precious) space on your module/layout to accomplish the same prototypical S curve and trains will glide right through it without derailing. There is even a website that will draw the curve for you on your printer, with no CAD software involved at all. Hope this gives you some ideas.
I ran 14 cars last weekend using the GP35 on MTL track. The consist was: 1 50' MTL Gondola, 1 40' MTL Gondola, 3 x Robert Ray Wooden Covered Hoppers (50' I think), 4 x Pennzee 50' PRR Hoppers, 2 x 31' FR PRR MOW Brass Hoppers, 2 x Full Throttle 51' Cylindrical Hoppers 1 x 50' MTL Domino Sugar Boxcar. No slippage at any speed, very slooooooooooooooow running as well. The GP35 never even got warm... I would go for the 2.4% grade for one reason-you can protypically double header or even triple or quad them which was VERY common for the PRR & NYC railroads here in the east.
