steam roster vs Helix

[Flagler]

I have some Intermountain AC12 cabforwards,Athern Challenger and Big boys.I plan on using Ashland designs helix with the kato elevated track. I think the radius is 15 and 16 1/2. 2% grade.Will I have truble pulling 20-25 car freight trains with these  engines

[Baronjutter]

I'd worry about that grade.

I run modern diesel and I have a short 2% grade ramp on my layout.  After building it I did some tests because I plan on building a helix later.  I got my biggest best loco, a huge kato 6 axle, and kept adding box cars until it couldn't go up the ramp anymore.  At only 2% I only was able to reliably haul about 18 cars up.  I then did the same test with one of my smaller dash 8's and was surprised it could pull nearly the same amount, even though it was a lighter smaller loco.  Next I tried another loco,  6 axle but only about as long as a dash-8.  It could barely pull 14 cars up the ramp!  I guess more wheels distributing the same weight means less grip per wheel on the tracks.  Now this was all properly weighted box cars on plastic wheels.  When I threw on my kato double-stack cars with metal wheels my loco's could pull about double the length. 

You're running steam though, which means even more wheels to distribute that limited weight.  And don't forget that the curve its self adds to that effective grade.  I don't know much about steam, and I know some have traction wheels, but I also know big boy's don't like tight turns.  If I was running huge steam like you plan to I'd be very wary at such a tight helix.  Maybe others with more first hand helix and steam experience can weigh in though.

[glakedylan]

ashlin notes ~2% grade, but if you do the math it is more than 2%
I have the same kit from ashlin and decided to cut my own subroadbed
and use the 17-5/8" and 19" track from Kato
this will provide much closer to 2%
still, I still doubt think it will be capable of handling more than 8-10 cars
on the climb

kindest regards
Gary

[CodyO]

To have about the same helix grade wise and used the same track
I'll do a test with my cab forward and big boy and let you know

Good choice on the unitrack!

[Paradise275]

I bought the HO Ashland helix to give myself a larger radius.

Rick

[glakedylan]

I bought the HO Ashland helix to give myself a larger radius.

Rick

will that really accomplish what you desire?
the HO helix will provide more clearance between levels
which will increase the grade %?

respectfully
Gary

[nkalanaga]

If the HO helix is simply scaled up, with a larger radius in proportion to the larger separation, the grade will be the same.  If the proportions change, and the radius doesn't increase as fast as the separation, yes, the grade will increase.

I know nothing about these helixes (helices?).  If you can build them with whatever separation you like, then using the HO radius with the N separation will give a lower grade.

[eric220]

Grade does not scale, it remains constant. 1" of rise in 50" of travel is 2%, whether the stuff going up it is Z, N, HO, G, or 1:1. In theory (not being familiar with the products) the HO version should achieve larger separation by having a larger radius at the same grade. The larger radius yeilds more liner travel per turn, which at the same grade yields more rise per turn.

[Flagler]

I can pull trains this long on a 2% straight grade that is 8 ft long.I am worried about the extra drag from the curve.
Maybe the 28 1/8" radius is best with the HO helixes

[Paradise275]

Depending on the elevation rise you need, you can reduce the space between the turns and thus reduce the grade.

Rick

[djconway]

What is the rise?
Assuming a 2" rise the grade on the 16.5" would be 1.93%
the same 2" rize would be 2.12%
Keep in mind that increases in curvature will cause the effective grade to increase.  A 2% grade on an 18" radius curve will cause less rolling resistance than a 2% grade on a 15" curve.
Flange depth, pizza cutters vs low profile will have a noticable difference in rolling resistance

[glakedylan]

the problem with the HO for N scale use
is the upright supports are cut/notched for HO clearances
thus, while you are extending the linear distance for each loop
you are employing a great clearance vertical in each loop
as the HO vertical clearance is more than N scale
the only way to compensate for what you note as an idea
is to use the HO kit for subroadbed and upright supports from
the N scale kit, giving you the ~2" clearance with the increased
linear run resulting in a lesser grade/incline %.

respectfully
Gary

[mmagliaro]

Typo fixes!
----------

I don't own the big steam you list in your question, so I can't say for sure if they could pull a 20-25 car train up that helix.
I've had several much smaller engines do it on a 2% 18" radius helix, so I bet they can.

But I have misgivings on curves that tight on a 2% helix, in general.   I always wished my 18" helix was broader to make
things easier on the climbing/pulling stresses and to reduce derailments.

One more thing.  Ashlin now states that their helixes are all made with 1/4" MDF even though some of the photos still show plywood.
I am *really* not a fan of that idea.  MDF absorbs moisture and sags more than plywood.  Even the tiniest bit of sag between the supports of a helix is deadly.   I made mine from 1/4" plywood.  There were places where I had to go back in and add extra supports or rods to "prop up" a tiny sag here and there.  If that track base sags even 1/16" between two supports a foot apart, it will mean derailments.

[North Bank Road]

Hello, I quite agree with Max that the MDF will eventually be a big problem. Plywood is the the way to go. I have built several helixes and if at all handy, easy to build. I too have steamers and have not had any problems with my 2% grades. I tested all before settling on 2%, but my radius is much larger at 22 inches. My simple solution was to get full sheets of plywood and cut as big a circle as I could. This left only one joint to make in each turn and allowed all risers to be mounted on the outside. Much easier for cleaning. Lessons learned the hard way! I also used pine blocks for risers vs the prior build using threaded rods and metal plates. I think I still have the scars from those plates visible on my arms. The larger radius allows for more clearance for fingers and re-railing of cars. The lumber left from these were used for a oval helix, though created more joints to dealt with.

Smaller steam can benefit from a powered boxcar or passenger car. Randgust offers a conversion weight set on line that I used for a 50' REA boxcar for passenger or freight. It still offered room for a decoder too.

Hope this helps....

Rick

[CodyO]

Used MDF on ours no problems to report

Northeastern Pennsylvania so hot summers cold winters

But as promised

Big boy can pull 18
cab forward 16 cars.
 7/8 oz. 40' box cars
Metal wheelsets accumate couplers