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Rail Road Track Turns

post #1 of 27
Thread Starter 
As an instructor we/I use these a lot in are teaching to get students to progress out of skidded turns and into nice parallel turns. We always say there is NO rotation going on, when in fact there MUST be!! For example, take 2 circles that are exactly the same, pretend that one is the inside and one is the outside ski. Sooner or later the circles will over lap. The same thing would happen if both skies followed the same arc, which is what we are told is supposed to happen, they're suppossed to follow the same arc. To keep the skies from crossing we must be steering one ski or the other slightly. Any input on this?
Next, if everybody, or almost everybody agrees with the formentioned, it is safe to ask: which ski should be steered? the inside or the outside?
I know it doesn't really matter, put we all know PSIA, there must be an answer to EVERYTHING!
post #2 of 27
You could bend one more than the other. Then they would never have to overlap. The Atomic 9.11 carving ski had a 10m outside sidecut and an 11m inside sidecut for that very reason.
post #3 of 27
Thread Starter 
Good point. I didn't think about the different side cuts! THanks
post #4 of 27
In railroad track turns, the idea is to start your turn with no rotation, just by tipping your skis on edge. This starts a very long radius turn where the difference in radius between the inside and outside ski doesn't cause them to cross immediately. If you do them right, the turning forces build and there is a passive weight shift to the outside ski, which bends more and eventually shortens the turning radius. At some point the inside ski becomes lighter and straighter (from less pressure) and needs to be steered to avoid crossing the outside ski, but you can usually get a couple of looong radius turns in before that happens. This drill is fun because it gets fast real quick even on green terrain. You steer your inside ski because your ouside ski is more heavily weighted and hooked up on edge. Your inside ski is lighter and therefore more steerable. You can't bend your inside ski more than your outside without putting more pressure on the inside than the outside, the ski with the most weight on it will always bend the most. Skis with asymetrical sidecut are a gimmick the appears from time to time but has little value for most skiing IMHO.
I'm frequently surprised that, even pretty good skiers on very easy terrain, can't/won't tip their skis on edge without some rotation. It seems to me the easist thing in skiing and a great way to learn to carve.
post #5 of 27
Along with Jdowling is saying, one excersize for this is tuck turns, Get into a low tuck position on the top of a green slope and begin moving down hill, the only way to turn is to use edging and the sidecut of the ski, it is extreemly hard to use rotary when in this position. Also this excersize is brutal on the legs if done over a few runs.
post #6 of 27
Just make sure you use proper form. When tucking on the green slope, you must put your poles in your armpits and pointing straight up. Maybe even forward a little. When you get tired of that, you can sit on your tails for a while.
post #7 of 27
If the snow is firm enough to do RR track turns on then increasing the pressure won't bend the ski more it will just make a deeper groove in the snow surface.

To leave two clean Parallel arcs in the snow what is necessary is to tip the inside ski a little more than the outside ski. This increased tipping will let the inside ski bend more than the outside ski and carve a tighter turn than the outside ski. This is why it is so important to emphasise the active use of the inside foot/leg in teaching others to do RR track turns. Its also important to make sure that the inside ski lead is kept to a minimum as too much ski lead seems to limit the degree of edging that can be achieved with that inside ski.

post #8 of 27
Thanks Ydnar

I was getting a little tangled in that... I KNOW I am only edging -no steering - when I do them well - but was a bit confused about the rest
post #9 of 27
An exercise I've used that works into RR turns is this: On a relatively level terrain which the student is very comfortable on, I get them to point their skis across the hill. Take the uphill ski and lay it HARD on its age (they can feel the pull in the uphill knee, not a comfortable position). Weighting that uphill leg (the downhill leg is along for the ride) they start moving across the hill. Of course, due to the sidecut of the ski, the ski will start turning into the fall line, speed accelerating. It's a really cool moment when they understand HOW the sidecut works, and begin to TRUST their edges. There is NO rotary movement at all, pure sidecut/carving.
post #10 of 27
Ahhh, But then, when is rotary not really rotary?

On a highly edged ski rotary simply increases the PRESSURE!
post #11 of 27
What would you call the mechanism used to steer a highly edged ski?
post #12 of 27
Originally posted by milesb:
What would you call the mechanism used to steer a highly edged ski?
Physics! An edged ski will turn just fine on its own with no active rotary (femoral rotation in the hip joint) necessary. There certainly is femoral rotation (from neutral) needed to flex the hip and edge a ski but once there nothing further is necessary.
post #13 of 27
VSG- What you descibe sounds like what we call "outrigger turns." The idea is to get the outside ski carving on as high an edge as possible- even higher than the dynmaics of the turn can support. The inside ski can carve or stay flat and skid depending on the student's ability/courage. The next step is to flex the inside leg as much as possible while extending the outside leg fully. Directions like "Don't think about anything but getting your outside on as high an edge as possible" help to get the student focused. The next step is to get the student to change edges/start a new turn without raising the hips vertically, by extending one leg and flexing the other simultaneously. The final step is to get the inside edge of the inside on a high edge. This drill gets real fast and is real fun. Everyone smiles the first time the energy from two skis on high edge shoots them into the next turn.
When you really get on a high edge like that, the inside gets very light and steers easily. Look at pictures of GS or Super G. Their outside leg is fully extended, their inside leg fully flexed, and often the inside ski is off the snow or barely touching, very straight or even bent away from the direction of the turn. More often than not, the inside ski is noticeably less edged than outside, showing that they must be steering, not carving.
Railroad tracks (in my terms)is a less intense but still fast drill. The goal here is to make a simultaneous edge change at turn entry with no rotary. Steering doesn't need to come into it unless the radius of the turn gets shorter, as it does as speed builds and higher edge angles increase. In my experience, most people at that point in their ski career will spontaneously steer or otherwise control their skis well enough to avoid crossing.
Miles- Steering an adged ski is only possible if it has less weight on it than the other ski. The high the edge, the less weight can be on the ski when you steer it.
Si- I never thought about rotating to increase pressure, but now that you say it maybe that's what happens in short radius turns. I'll have to experiment with that next winter.

My mother says I should sell my computer, buy a car, move out of the basement and meet a girl. Is she right? Has anyone actually tried this?
post #14 of 27
Okay guys, If you are making "dynamic railroad" track turns you will necessarily be on high edge angles with both skis. So what must I do to add steering to my inside ski to tighten the arcs? (Because of the high edge angle it isn't femoral rotation.)
post #15 of 27
Originally posted by John Dowling:

My mother says I should sell my computer, buy a car, move out of the basement and meet a girl. Is she right? Has anyone actually tried this?
Why do I want to meet a girl ?
post #16 of 27
Thread Starter 
I was always told/taught in clinics, both PSIA and at my resort, that RR Track Turns were supposed to leave identical tracks in the snow. This would mean the same amt. of pressure would have to be used on both skies and the same amt. of edging as well. So far I think that the best explination for not using rotary, it in fact we aren't is because of the side cut. Thanks for everyones input!
post #17 of 27

I would not describe the two tracks left by the skis in RR turns as identical. If you hike back up and look at the tracks you will see that the groove left by the outside ski is a little deeper in the surface of the snow than that left by the inside ski because of the natural transfer of pressure to the outside ski of a turn. What's important is that both tracks are very thin grooves in the snow that show no sideways movement of the ski. The theroy is that the entire length of the ski passes over the same piont. It can be debated whether such a pure carve is possible but the RR turn is as close as we come to it.

Some people contend that the inside ski must be steered because greater pressure on the outside ski would cause it to bend more and therefore carve a tighter turn than the inside ski. This doesn't happen because applying greater pressure to an edged ski on a hard snow surface won't make it bend further, it just makes a slightly deeper groove in the snow surface. This is because the ski is in contact with the snow along its entire length so the snow acts as a "stop" to keep the ski from bending further. If we want the ski to bend more we must tip it up to a higher edge angle. This will lift the center of the ski off the snow surface while the two ends of the ski stay in contact. The pressure on the ski will then bend the ski untill it is again in contact with the snow surface along its entire length. The ski will now carve a tighter arc on the surface of the snow. You can demonatrate this to students with a business card with smooth arc sliced into one side of it. Place the card on the surface of a table and show them how the greater the edge angle the more the card can bend and still keep its edge on the table surface.

From the above it follows that if I tip my inside ski a little more than I tip my outside ski then I can have that inside ski scribe a concentric arc inside the arc of the outside ski. It also explains why it isn't necessary to try to keep a lot of pressure on the inside ski, we only need enough pressure to bend the ski untill it contacts the snow surface and with the modern shaped ski with its relitively soft flex there isn't a lot of pressure required to accomplish this. As I said above if I focus on tipping the inside foot/leg I can accomplish this goal of tipping the inside ski a little more and carve parallel tracks for as long as the hill will let me.

Hope this helps explain why there is no steering/rotational input needed to do the exercise.

post #18 of 27

Well done, I like your clear explanations. One point that I add when I work with others on the RR turns is that with both lower legs angulated they need to get a bowlegged feeling in order to edge the inside ski more than the outside ski. This is a funny feeling at first, but once they get used to it they can easily create parallel tracks.
post #19 of 27
Last year I went to the National Acadamy with this question in mind. I found that many of those people had little idea of what was going on. I carved several 360 railroad track turns at the bottom of Pine Martin to prove that the inside ski carves a shorter radius turn.
My theory at that time was to cant the boots the way Witherall said in the Athletic Skier(2 deg negative) That way the inside ski has 4 deg more edge angle when shins are parallel. Most WC skiers are not canted this way yet they leave a track with the Inside ski carving a shorter radius.
I did not get a chance to discuss it at length with Ron LeMaster but I found the answer in his book, The Skiers Edge. The sidecut of the ski gives it a "steering angle"(positive at the tip, negative at the tail). By pulling the inside ski back, we apply pressure farther towards the tip where the steering angle is greater, thus allowing it to carve a tighter arc with less weight on it.
post #20 of 27
Originally posted by SLATZ:
...I did not get a chance to discuss it at length with Ron LeMaster but I found the answer in his book, The Skiers Edge. The sidecut of the ski gives it a "steering angle"(positive at the tip, negative at the tail). By pulling the inside ski back, we apply pressure farther towards the tip where the steering angle is greater, thus allowing it to carve a tighter arc with less weight on it.
Sorry, Slatz, but I don't think your comments on the steering angle are correct.

The (local) steering angle is the angle between the engaged edge of the ski (at the point you are looking at it), and the direction that snow is going by under that point (ie, as if you had a small videocam mounted to your skis looking directly downward at the snow streaking by underneath the engaged edge).

In a pure carved / RR turn, the local steering angle is by definition exactly zero along the entire length of the edge. Put differently, a given spot on the snow will move towards the rear of the ski, always remaining directly under the curved edge. Described a third way, the entire edge of the ski passes over a given spot on the snow in a pure carved turn.

The steering angle *only* deviates from zero (locally) if there is some skidding going on, and that situation isn't a pure carved turn.

The part of the LeMaster book that I think you are referring to (ie, steering angle positive at the tip, negative at the tail) was meant to explain why there is still a turning force in the correct direction, even on a slightly edged, skidding ski (ie, why you don't have to be making pure carved turns to have your skis automatically turn for you without supplying active rotary input to them).

Hope this helps,

Tom / PM
post #21 of 27
Interesting! I guess my question isn't answered after all.
What's your "take" on it? Do we go back to the edge angle thing? A lot of WC skiers appear pretty bowlegged. Their tracks are definetly parallel, indicating a shorter radius of the inside ski. They're quite clean and about equal depth.
My physics education is pretty basic(high school and tech college in auto mechanics) I've been a hot rodder, mechanic, shop owner/operator and auto mech instructor all my adult life. Skiing, like hot rodding, for me, is a blend of artistry, innovation and physics. I'm always looking for the basic principles involved.
post #22 of 27
Could it have something to do with the different sidecuts on the front half vs. the back half of most skis?
post #23 of 27
Hi Slatz –

Your 360 RR tracks with concentric circles must be beautiful to behold! Good skiing!

Anyway, I think Ydnar (& maybe others – I didn’t read the whole thread) gave a really excellent explanation of what is going on in this type of turn.

Correct me if I am wrong, but after re-reading your last post, I think your real concern is how exactly do people get the inner ski to carve a slightly tighter turn, especially if they are not using Witherell’s canting scheme to get a bit more edge angle on the inside ski.

I think Norefjell nailed this question on the head: Namely, they push the inner knee more into the turn than the outer knee and wind up a few degrees bowlegged. To me, it feels like a lot more than a few degrees, but that’s all it really takes. I should point out that when looking at photos of skiers in RR-track turns, one should pay attention to the angles of the ski bottoms, and not to the angles that the legs are making since the latter can be affected by cants, plates, cuff adjustment, etc.

People sometimes suggest a difference in fore-aft pressure distributions between the two skis is used to obtain the different carving radii. While fore-aft differences between the two skis are common, it does not yield different radii in a pure carved turn on hard snow for exactly the same reason that pressing harder on a ski at a certain edge angle does not make it flex more in hard snow. Namely, you can change the fore-aft pressure distribution all you want, but as long as the tip, waist and tail all remain in contact with the snow & no part gets so light that that section of the ski starts to skid (its no longer a pure carve if it does), then simple geometry dictates exactly what radius turn will be carved.

Milesb suggested the fore-aft difference in sidecut could play a roll in this issue. Changes like this don’t have anything directly to do with generating the necessary difference in carving radii between the inside and outside skis. The main thing that they do is slightly change the flexed shape of the ski when the waist is bottomed out on the hardpack. For example, take the hypothetical case of a ski whose tail is as wide as its tip, and the ski waist (and center of the boot) is located at the exact center of the running surface. In this case, the flex of the forebody of the ski will be exactly equal to the flex of the aft section of the ski. On the other hand, if everything else remains the same, but the width of the tail of the ski is now reduced slightly, then the rear of the ski will flex slightly less than the tip in a pure carved turn.

Note, however, that you can’t arbitrarily change the tail width (or any other dimension) without making compensating changes in some other variable like the fore-aft position of the waist. If you don’t do this, then the front of the ski will want to carve one radius turn and the back of the ski a different radius turn, and the net result will be a ski that can’t ever make “absolutely pure” carves. Designers often intentionally introduce asymmetry in fore and aft sidecut radii to (a) reduce the tendency of the ski to be a “one-trick pony”; (b) help the ski smoothly transition between carving and skarving, etc.

Tom / PM
post #24 of 27
I've seen discussion here about "pressuring". I would maintain, just for clarity on the subject, that while we can move pressure around from foot to foot, we cannot "apply" more pressure than our mass allows. We've discussed that we can apply pressure on the inside ski to tighten its arc, and in order to do that, we need to take some pressure away from the outside foot. It may work just as well to say "lighten the outside ski to tighten up the radius of the inside ski."

Another option we have is to apply a little leverage to the inside ski when our "pressure options" have been exhausted. This has also been said (I forget who it was and now I can't find it!) when it was mentioned that we can pull the inside foot back a little. When this is done, the shin contacts the boot cuff a little and applies a little bend to the shovel of the ski. If that ski is on edge, the radius will tighten! This is by no means an efficient way to ski, but it can be a decent TACTIC when things get hairy.

Actively tipping the inside ski is certainly where it's at. When we get a little lazy with that action, we have to apply a bit more rotary and we skid. BANG! RR track turns went Bye, Bye!

Tom Burch. Even though the skis are on high edge angles, a subtle amount of Femoral Rotation (subtle and deliberate will result in a bit of bending in the ski. Too harshly will wash your tails out!) will have a profound effect on the radius, as would levering, or Long/short legging it, or any number of things. The best thing to do is find a focus that works, practice it, and then look for another focus and make it work. You'll find that, before long, you'll have an entire boat-load of Tactics to get you out of trouble!!!

In closing, there are many different ways to tighten turn shapes, and a focus on the TIPPING skill would seem the logical answer to this question in my eye. Be careful when working on "applying pressure". More often than not we only end up "levering" and that has many pitfalls. Pressure is something that is pre-ordained... It HAPPENS to us. We don't exert it, we go through phases where we defy it, and absorb it!!!

Good Posts Everyone!!!! You'd be amazed (or maybe not) how difficult some people find it to just TIP the ski without adding any rotary input! It's hard watch instructors and students alike make a sweet run, and then have to tell them "look at your tracks. Your inside ski is skidding. We'd better try that one again!"

Beer tastes good tonight,
Spag :
post #25 of 27
When I read threads like this one, all I can think about are skiers who have no business on super side cut skis. They're making the hill even more dangerous, because all they've been told is that "carving is where it's at". I get the feeling they're working from the top down, not the bottom up.

Sure, as a skier, you want to ski on the $500 part of the ski, not the $50 part. You want to learn movements, that train you, to ski on your edges.

But me thinks skiing the $500 part of the ski is the result, not the cause of skiing. If a skier is taught well, they'll learn to make turns by tipping - skiing with their feet, not their body. They'll learn turns and technique that can be universally applied, not just on groomers, or on short, super side cut skis.

There is one thing that's great about this whole "modern skiing" thang. The industry, is gearing instruction towards the groomers - the carving rage. Because, groomers are where the money is. And it's a fact, that most skiers will never ski anywhere but.

So let the rage continue. Because, you instructors are preaching technique and equipment that's very limited. So what that means is that you're preserving off-piste skiing and that it will always be "dorkless". Good for me, bad for skiers who want to go there.

post #26 of 27

Saw a few of the types you are talking about a couple seasons ago and more this last season. These are people who have never skied on anthing but a shaped ski and have learned a ride the edge technique of some sort, very static looking skiers. Throw in the "hockey stop" that they have learned and they feel ready to ski anywhere on the mountain. But the reality is that they are going where the ski wants to take them rather than where they want to go. This can be dangerous. These people have not learned the skill of controlling the interaction of the ski and the snow surface. They have learned only one little part of this important skill, how to make the ski carve.

It will be interesting to see what kind of skier will result when a carve oriented skier with a harsh hockey stop moves to steeper terrain. Will they become a linked hockey stop king? Or will they decide that steep is too fast and restrict themselves to blue groomers? Or will the steep terrain force them to blend the carve and the pushy, skiddy hockey stop into a nicely shaped turn where they have control over there turn shape?

In regards to the third possibility above, I don't think so!!

post #27 of 27
Great thread. I've been away for a few months with my head burried in summer stuff. What away to wake up and realize that the season is less than 90 days away!!!!!!!!!

Most instructors I've worked with in the past few years realize that new gear and movements give us more options; carving, skidding or blened turns. What I've seen taught on the hill for most customers leans towards blended behaviors. We instructors are enamored with carving because it has been the 'Holy Grail' for so long.

Skiing with a square stance, similar leg/edge angles, and little tip lead encorages the tip of the inside ski to engage 'more' than the outside ski usually this will tighten the arc.

When this happens and both skiis scribe a carved arc in the snow there apears to be rotory motion in the feet and legs because the feet travel farther than the torso.

The rotory that is used(when a true carve happens) appears to be more an isue of balance and a result of ski snow inter-action while allowing the feet to travel in a longer arc than the torso.
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