Update on Helix


Greg Elmassian
 

Well, did my 3rd mockup on the helix.

http://www.elmassian.com/index.php?
module=pagemaster&PAGE_user_op=view_page&PAGE_id=68&MMN_position=89:1
2:49

The last picture show the rail sections joined with Split Jaw
clamps. Obviously more sturdy than the stock Aristo SS joiners. (and
more expensive!)

I rolled several long cars down the helix, looks like it might work.

And I ran a USAT F unit down, and back up under it's own power.

The diameter is 88.5 inches, and the clearance from the outer rail
to anything is 4.5 inches. That gives enough clearance for my
longest cars. The overhang king seems to be an Aristo heavyweight
passenger car, with the steps hanging down, it's those steps at the
very beginning of the car, and hanging out from the sides of the car.

My tallest cars are the USAT container cars, but they don't overhang
the most, because the car is a lot longer than the double stacked
containers.

Greg


Stefan Gerris <s.gerris@...>
 

Hi Greg,

Nice to see come activity on this list again!

Looking at the pictures, one would almost think the space was created
especially for the helix ;-). Clearances seem to be just within limits,
great!

What I'm a bit worried about is the grade. It looks to me like it is a bit
steep if you intend to use it "uphill" as well. If you add the increased
drag from the tight curve, it might be a bit much for an average engine
with an average length train (what's average in your case?). Have you
tried this? Do you have room (heigth) for an additional loop? Or maybe
elevate the stretch of track that is now on the floor in order to flatten
out the helix...

But than again, maybe the picture is giving me a completely wrong
impression about the grade. Have you measured it (how much is it ;-? )?
Maybe you'll have to fit a speedbump at the bottom to prevent speeding =P

Cheers, Stefan


Greg Elmassian
 

Thanks Stefan, it's hard getting yet another garden railways group
started. Am trying to post more often.

I intend the loop for down travel only. I might find though that
long trains will bunch up and derail. I did run a single F unit up
it just to see what happened. Seems to be about 5% or more grade,
will calculate it.

Another loop would make the clearance between the tracks too small
for the locos, need about 10" minimum plus the thickness of the
structure that will completely support the track.

For continuous running, since I run DCC, I might crank up the back
emf setting so that the train will run at constant speed uphill or
down, it can be done.

This is a shortcut to allow continuous running of shorter trains
while being able to see the whole train from the back yard.

It's the only non 14' diameter track in the outer loop. Eventually,
the track will go past this part, and then go out to the front yard,
where I can use 14' diameter to get it back to the other end of the
loop.

Regards, Greg

--- In sandiegogardenrailways@..., "Stefan Gerris"
<s.gerris@...> wrote:

Hi Greg,

Nice to see come activity on this list again!

Looking at the pictures, one would almost think the space was
created
especially for the helix ;-). Clearances seem to be just within
limits,
great!

What I'm a bit worried about is the grade. It looks to me like it
is a bit
steep if you intend to use it "uphill" as well. If you add the
increased
drag from the tight curve, it might be a bit much for an average
engine
with an average length train (what's average in your case?). Have
you
tried this? Do you have room (heigth) for an additional loop? Or
maybe
elevate the stretch of track that is now on the floor in order to
flatten
out the helix...

But than again, maybe the picture is giving me a completely wrong
impression about the grade. Have you measured it (how much is it ;-
? )?
Maybe you'll have to fit a speedbump at the bottom to prevent
speeding =P

Cheers, Stefan