Flex Track Incline-Turn Ratios

[AirborneAFOL]

I have, after months of quietly researching this forum, finally acquired 60052 (Cargo Train) to my city layout. I came to conclude (thanks in large part to many of your assessments on these boards) that it was the ideal "first train". A portion of my track layout runs through a "mountain tunnel".

Apologies if this is addressed elsewhere - or my question unclear (still a rookie on the proper terminology)...

Has anyone else has run into the problem of losing traction when exceeding 2-flex-tracks continguously at the standard elevation? My elevation is 2/3 "brick" height per 16 studs distance. When using 3+ links of flex track in an elevating curve, however, traction fails with even a single car.

The obvious solution would seem to be leveling the grade when employing flex track - but I'm wondering if perhaps reducing the curve I'm using 3+ flex track to create would do the trick. Being as this segment is running through a tunnel, I'm curious if there's a good rule of thumb that would save a good bit of experimenting/rework on the mountain itself...

[Redimus]

You've got two problems, first off, on their own, the flexi track creates a fair bit of drag compared to normal rails because it is effectively a has a continuous check rail to lead the train round sharp curves causing more of the wheels to rub against the rail. Secondly, even normal Lego curves are quite prone to drag due to their sharp radius, and I suspect that flexi track can achieve slightly sharper curves (although I may be wrong on that one), add that to the incline, and I can see how trains are grinding to a halt.

Also, how are you creating the incline? On normal track you can probably get away with just adding some plates at the end of each rail, but flexi track tends to be a bit too flexible in the up and down axis to do that, you may find that it isn't rising at a consistent level, rather it just rises sharply then levels out, which would make for a much harsher gradient.

[AirborneAFOL]

To create the incline, I've effectively placed 1-plate under the first flex "segment", and 2-plates under the 3rd "segment". I can definitely see what you're saying in the twofold problem - compounded by the vertical flex the track is prone to.

I suppose this leads me down the path of "no inclines on flex track curves", unfortunately. I'll tinker some over the next few days and report back if I can find any flex curve-incline ratios that seem workable at low speeds, however...

I suspect that flexi track can achieve slightly sharper curves (although I may be wrong on that one)...

I can confirm you are correct on this point. I've been able attain slightly tighter 90-degree turns using flex track (the turn completed about 4-studs sooner than using fixed "curve" track) - and without any performance impediments (albiet with level grades).

[AirborneAFOL]

After some experimenting last night, I found the following configurations of flex track allow smooth performance:

1. No more than 2-segments of flex at the "maximum" turn angle (slightly sharper than a standard curved track, completing 90-degree turn 4-studs sooner), along a 1-plate-per-16-studs elevation grade.

2. 3-segments of flex at a "standard" turn (equal to standard curve track), along a 1-16 elevation grade.

3. 5-segments of flex at a "reduced" turn (completing 90-degrees in 4-6 studs further than standard curve track), along the benchmark maximum 2-16 elevation grade.

4. Unlimited segments of flex at the "maximum" turn, along a flat grade.

Of course, all of this is running a single PF motor (60052) pulling anywhere from 1-4 cars.

Linking up a second motor on the 3rd car (or later) elimated all performance impediments, and can run smoothly across unlimited segments of flex at the sharpest possible turn and at a 2-16 elevation grade; the first/second motor would effectively push/pull the other one through the segments of high-friction. Of course, MOD'ing a freight car with a motor opens a whole different can of worms...

Perhaps someone (with greater train expertise) would care to validate this experiment, and we could have flex track turn/elevation guidelines archived for future reference?