# wondering about transitions



## bmwr71 (Jan 30, 2010)

Have trouble finding time to look on the forums from all the email I get. One of the regular things I get is the Model Railroad Academy teaser videos and saw one the other day on stopping derailments. One of the things mentioned was transitions. One was transitions into curves and I get that would probably be in the realm of flex track. They also spoke of transitions for grades, going up or down hills. I imagine that would involve bending track vertically bowed up versus horizontally as with a curve transition. Does anyone do that in G?

Also wondered if anyone ever makes their own rerailer inserts between rails say for bridges? 

Doug


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## David Leech (Dec 9, 2008)

Hi Doug,
It probably depends on what you run and at what speed!
I run live steam at mainline speed so transition curves are essential for the amount of weight needing to change direction, plus it also looks more realistic.
My track is reasonable level, so I can't comment on vertical transitions.
Regards,
David Leech, Delta, Canada


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## fsts2k (Jan 13, 2009)

Agree with David, I put in transitions in my live steam layout and it helps the trains run and look more smoothly. That said, I bent all my own curves with a bender, I did not use sectional track


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## Pete Thornton (Jan 2, 2008)

> They also spoke of transitions for grades, going up or down hills. I imagine that would involve bending track vertically bowed up versus horizontally as with a curve transition. Does anyone do that in G?


It happens when someone steps on the track, without any warning. 

As you note, flex track makes it easier to handle transitions. We do try to keep our hills down to a manageable 3-4% grade, and it is not clear you need to do any bending to make that happen - although with flex track you may have to, to make it perform a smooth curve.

Incidentally, with non-flex track, you can make a curve transition using wider radius curves at the start and end of the curved portion, with tighter radius in the middle parts. It makes track planning more difficult, but performs the job of a 'transition' into the curve.




> Also wondered if anyone ever makes their own rerailer inserts between rails say for bridges?


Bridges don't usually have re-railer sections. I think you might be considering the 'guard rails' which parallel the running rails, usually inside. The idea is that if you get a derailment the wheels are kept on the bridge by the guard rails so the catastrophic fall is averted 
The crew gets to re-rail the car when they get safely to solid land.


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## kormsen (Oct 27, 2009)

needing transitions for curves depends on more than one factors.
you got enough space?
you want to run long roling stock?
you like high speed trains?
you hate to see the cars of a train "jump" round the corner entering and leaving curves? 
if, and how much transitions you need/want depends on the answers to these questions.

the use of flextrack or sectional depends as well on your variables.
what do you want to buy and pay? (R1 rebent second-hand curves are the cheapest option)
flextrack makes for nicer, softer transitions and smoother rides.
sectional track has less problems with expansion and retraction from the weather.
(and if you like the "clickety-clack", sectional is a "must".)

i use only short locos (0-2-0) and short cars (max 14") because i have two 6% grades.
for the transitions i bended two one-foot sections at 3% up or down each.


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## Dan Pierce (Jan 2, 2008)

Is that 0-2-0 called a kangaroo??


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## kormsen (Oct 27, 2009)

Dan Pierce said:


> Is that 0-2-0 called a kangaroo??


OOOPSS!

i counted axles, not wheels.

*it should say: 0-4-0* 
(mostly Stainzes)


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## PaulRace (Apr 30, 2020)

*Easements*

RR's call these transitions Easements. They reduce your locomotive lurching into and out of curves. 

Yes, they're easier to do with flex track. 

But they can be done with pre-curved track as well. If you use track that turns at the same angle, it's pretty easy. For example, if you're using 4'-diameter curves, you can use 5'-diameter curves to do transitions at both ends of the curve. If you're using 5'-diameter curves, you can use 10'-diameter curves at both ends. When I was using mostly 10'-diameter curves and it was easy to pick up a few 20'-diameter curves, I would use those as easements. All of those are typically 12 to a circle, so each piece bends 30 degrees. 

If you're using R3, 8'-diameter curves, your options are a little more limited. Aristo used to make 16' diameter curves that had the same bend as the 8'-diameter curves. I don't know if anyone is making them now. 

Why are such provisions helpful? When a locomotive is on a straightaway, the weight of the locomotive causes it to ride evenly between the rails, with the flanges barely touching the rails if they do at all. When it enters a curve, centrifugal force pushes it toward the outside rail. Not only do the flanges out the outer wheels bump the rail, but the locomotive usually rides up a little, due to the angle of the wheel tread. 

Having more gradual curves allows the locomotive to ease into that position more gradually. 

More than you wanted to know, I'm sure. Best of luck!

Paul


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## Greg Elmassian (Jan 3, 2008)

Yep, easements on curves are great, helps prevent lurching, everything runs better. But very few of us have the luxury of having lots of space for the curves. I tend to go towards an overall larger & constant radius for the curve.


Vertical easements on grades depend on length of your cars, and how your couplers are mounted. Short cars with truck mounted couplers can take roller coaster track.


Long locos and cars with body mounts can have all kinds of issues, normally the couplers override each other and come apart.


Another interesting thing that happened to me was with Aristo 3 axle motor blocks, there is no suspension in them and if you crest a grade with a sharp breakover angle, the lead wheels will leave the railhead, if this happens enough, the flanges can clear the railhead also and you have a derailment.


I had this in a transition between a 3.5% grade and level, with 5 foot long rail sections. Pulled it out and used 1 foot sections to make a smoother and more gradual transition, problem fixed. (really hard to bend rail in vertical direction).


Greg


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