> 2.5%? Why Not?

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Trackside

Member
Hey guys,

I went back to the drawing board with my garage layout. I'm planning on a 2 level shelf layout, and I'll be using a helix at one end, and a long grade, at the other.

Anyway, I searched the forums, and I read 2.5% a lot, but I couldn't find any info on why that seemed to be what most would consider to be the steepest grade they'd do, especially on something non-prototypical like a helix.

Why not go 3, or 4%?

Is it simply for realism, or is it a performance issue too?

I remember my 4x8 I had as a kid; it was a double loop which crossed over itself, so it must have been 5% or more. The only problem I remember was that the 4449 lost some traction on the grade at some speeds. (I thought that part was cool)

Your thoughts?
 
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jbaakko

Diesel Detail Freak
Well I guess I can reply. 2.5% is "tough" but it really depends on the units your are using, train length & weight, and personal preferences. My dad's RR will top out at 3% but he'll be running 4000hp+ lashups, usually consisting of 2 or more units, with short, maybe 10-15 car max trains.

Wheel slippage does however damage rails, wheels motors and power supply...
 

IronBeltKen

Lazy Daydreamer
Another issue to consider is that a grade on a curve adds even more roll resistance to a train than the same-% grade on a straight track, probably because of friction between the flanges and the rails. The sharper the radius, the more drag.

Somebody once posted a formula to calculate the "effective grade" that gets created on a curve, but I can't remember where I saw it...[?]
 

RexHea

RAIL BENDER
It is very much a performance issue. Most engines by themselves will not have a problem going up a steep grade, but the more cars that are coupled on...the more you are likely to slip. Instead of having 10-15 cars you may only be able to pull 5. Where some slippage may seem ok, you have to consider the wear on your drivers.

As Ken said, the curves will add drag to the consist increasing the effects of the steeper grade. I had a perfect 2.5% grade with a 26" curve midway, but my engines would begin slipping after about half of a 12 car consist was in the curve. I had to adjust my grade to >2% to compensate for this. Steamers are particularly vulnerable to this.
 
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SDP45

I like TYCO!
Grades may not be an issue with an 0-5-0 switcher. Then you have to worry about coupler strength. :D
 

Trackside

Member
Well at the risk of offending my fellow railfans, I think steam power is lame. :eek: To me, they're nothing more than another passenger train, and out in the NW, they often have a diesel right behind them doing the work.

I was hoping you guy were going to come back and say that it was a more isolated issue with steam engines loosing traction. Glad I asked. :D
 

narrowgaugecdb

New Member
Dear Ross,
With all do respect for the diesel fans....
Nobody ( diesel locomotive manufacturer) has been able to produce a diesel locomotive that equals the performance of a steam engine. (real world)
Many diesels have to ride in consist to do the work of one Big Boy locomotive.
This is also true for other smaller steam engines.
I hope that this clarifies this misconception.
Constantin
 

jbaakko

Diesel Detail Freak
I think they were discussing the wheel slippage we all get in the way of Scale Steam...
 

Trackside

Member
jbaakko said:
I think they were discussing the wheel slippage we all get in the way of Scale Steam...
Yes - I was referring to HO and wheel slippage. :D I do think real world steam is lame though. Unless it's hauling freight like say in China, but I think steam power today is lame. :eek: I get much more excited seeing an all SD40-2 lash up, or 6 GEVO's elephant style in notch 8 creeping along a 2.2% grade at 5 MPH.

Steam trains are just another passenger train, except there's a bunch of people hanging out the windows waving like mad as if they're in a parade. :eek: :eek: ;) :p

Yes - I know this is like being a sports car fan, and telling the rest of the guys in the club that I don't like cherry red, but it's the truth in my world. :p
 
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jbaakko

Diesel Detail Freak
Trackside said:
Yes - I know this is like being a sports car fan, and telling the rest of the guys in the club that I don't like cherry red, but it's the truth in my world. :p
You don't like RED!?


HAHA...
 




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