How the heck do they bend track accurately?

Ta for the replies. Sorry I didn't make it clear. Of course every person & his/her dog know how pipes are bent.

What I meant is have you seen B&M's elements? Say Cobra Rolls. The pipe curving profile is outta this world. How is that achieved??

Hmm, sounds like Arrow were doing it manually in the old days, i.e. bending pipes bit by bit & rotating it as they go along. Therefore their track profiles are pretty standard. They're more like RCT, i.e. loop, turn loop etc. Hence their rough transitions. Not too sure how they do curving drops.

Now they all use computerised machines. Sounds like all are top secret!

I believe the B&M spine design is called tessellation - to form mosiacs using triangles.

Either way you look at, it can take upto 100+ passes sometimes to bend a rail into the right shape.

Also notice, if you look at each track section on a shape turn on a coaster, you will see that the rails for each section are not bent as shape as many would think.

B&M spines are made using poligonal forms instead of tubular forms. A rectangular box is made of two squares at the end. When the track is twisting, you can't bend the flat sheets that make the sides(or easily at least) so they subdivide the polygons. This is done in computer animation a lot. The track all has to conform to a spline curve.

Most of this is all obvious though.

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On one of the Discovery shows, they show how Morgan made the track for either Goliath or SD 2000. If my memory serves me correct, in their plant, they put sensor pins in the floor of their plant. When they would run the track through the bending machine & computer, it would use the sensors in the floor to plot out where the track segment is going to be located on overall coaster and bend it accordingly.

Granted, there are no elements like on the B&M coasters in question above, but I would assume that the plant that manufactures B&M track uses a process much the same.

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General Public said:
Just as a sidenote... railroad tracks aren't 'bent' anymore per se.

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Duh! Don't know why I didn't think of it, but when you watch old movies of the Panama Canal construction, you see cranes moving sections of track. The track is flexible enough on its own.

Oh well, I've made dumber claims...but so what? ;)

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"I go out at 3 o' clock for a quart of milk and come home to my son treating his body like an amusement park!" - Estelle Costanza

Mainline rails often have such a slight curvature that they are just flexed in long sections. However, the rails used in many yards and in industrial spurs have curves too tight to just be flexed and are still supplied in 40' long prebent sections. You specify the degree of curvature that you want and order the rail.

I just tried a reply that I don't think went through. If it did then this is redundent. The machine on the Steel Dragon 2000 show is a Roundo angle bender. You can see these machines at www.comeq.com. These machine can be computer controlled and I would guess the one at Morgan is. This feature allows for very accuarte mfg.