All-
Anybody know if anyone has ever devised an emergency brake (so to speak) system for a helix? And if so, are there any plans out there?
Every so often, part of a consist gets away – I can hear it racing downward inside Sean’s Hill (where he helix is hidden) and all I can do is hope the cars all come out the bottom on track and okay.
It’s a heck of way to find out a coupler needs replacing![:O]
Thanks
Craig Cooper
Find a big broom with soft bristles, or a couple of small ones like dustpan brushes. Cut one to match the outside of the curve (concave) and the other to match the inside (convex.) Mount these on a pivot so that the brushes come up to the rails from the side, a bit above the rails so they are at the height of the car bodies. Set them so they toe in a bit towards the downhill end of the helix. When the pivot is the “brakes on” position, the brushes will gently slow the cars. When the pivot is in the normal “brakes off” position, the brushes are retracted away from the helix and there is no contact.
You could activate this either with a big wooden lever, or, if you do nice bearings, with a Tortoise and some linkage.
Interesting! Have you actually tried it? Sounds like it might be a bit abusive to paint, grab irons and ladders.
I might try the same principle but with a soft cloth wrapped around cotton balls (or something) instead of brush bristles.
Thanks for the idea!
Craig Cooper
You could install a variant of the system Ed Ravenscroft used for working retarders in his hump yard - nozzles between the rails, pointed upgrade at a low angle (to minimize the upward component,) connected to a source of low pressure air. It would take some tinkering with the air pressure, but you should be able to slow the runaway to a safe speed - or even blow it uphill to keep the train together.
Now that I typed that, I might consider the same system for my own use. I don’t have a helix, as such, but I do have some long, soon-to-be-hidden grades, with more to come.
Chuck (modeling Central Japan in September, 1964)
Any possibility for helper operations ? If you have a number of cars break free, they’ll gain momentum & force.
I have been using helpers for just that reason.
It’s a bit time consuming and annoying to have a loco tied up for that purpose alone, expecially when the extra motive power isn’t needed.
Until I build some kind of emergency brake, though, I think helpers will be the way to go.
Craig Cooper
I haven’t built anything like this. And I’ll admit that I was concerned over the abuse of car sides. That’s why I specified soft brushes. Also, part of my thinking was that the alternative was more substantial damage from a high-speed, multi-car derailment.
You might be able to use a variant of this by raising something flexible but still somewhat springy up between the rails to engage the axles. This would probably be something more like wire, because you wouldn’t have as many “bristles” available. It would need to be near the rails, not in the center, so that it wouldn’t damage the coupler trip-pins.
Another option would be a “runaway ramp” like you see on steep highway downhills. This would be a turnout that would route the cars to a steeply-climbing siding which ends in something soft.
If you have a gentle helix and your trains are short, so that engine power isn’t a problem, you might consider felt strips close to the rails. This would brush against the insides of the wheels and provide friction all the time, which would slow a runaway but also put drag on a climbing train. This is an “always on” approach. I think it would be pretty tricky to move “brake pads” like this with any kind of linkage. Not a very good option, IMHO, but maybe someone else can think of a way to make it work better.
Still, I think your initial idea is a good one – I’m just going to use something softer and fluffier to “catch” the runaway.
If your helix is double-tracked, and one side is only used to go up the helix, then you might be able to use some kind of spring loaded ratchet type catch on the uphill track that would allow the cars to pass over from one direction, but would catch on the axles if a car began rolling down the hill. Place them every foot or so and any free-rolling stock would never gain much downhill momentum, so likelihood of damage would be low.
Anyone have ideas what to use for the catches?
Are you really anticipating couplers letting loose often enough to seriously consider adding something to catch the train?! Personally, I’d just make sure my equipment is in proper order so that I don’t have runaways. Putting something in to catch one is just adding complexity in order to avoid proper maintenance, it seems to me.
maybe pieces of copper/bronze, and thin styrene (like .05")? the little bits of copper/bronze used in the add-on power wipers seem pretty springy…
MisterBeasly’s runaway ramp using switches is the most logical idea I think. Place turnouts every few loops, put a solenoid (ie. fast) motor on it to a toggle switch that will activate the turnout(s) desired quickly and then the cars can be potentially saved.
Alternatively, a friend of mine came up with a clever idea involving infrared sensors. You place two sensors an inch or so apart, every level or two. As the train moves uphill, sensor one activates followed by sensor two. The circuit knows that one before two equals forward motion. Now, say a car breaks loose from the rear. As it rolls backwards downhill it trips sensor 2 first follwed by sensor 1. Now the circuit detects a train moving in the wrong direction than anticipated. It then activates the turnout motor directly downhill from it automatically and the train is “saved”. If the helix is being used as an up and down route… not just an uphill route, you can then have a toggle switch that you can use to deactivate the sensors for the downhill leg of the route… flip it back and its online again for the next uphill train.
Or you could just maintain equipment??? 
Anyone know an electrical engineer?
It seems to me that it would be much easier and cheaper to just install reliable couplers on all of your rolling stock so it doesn’t come apart when you don’t want it to.
Most of the problems I have had with cars coming uncoupled on grades is due to using a cheap McHenry coupler or other brand with no knuckle spring, or having a coupler that was too high or too low.
Using Kadees and a coupler height gauge nearly always solves this problem.
It only has to happen once to wreck a car or two you put a lot of effort into building!
Besides, couplers can get damaged and not appear to be damaged and work perfectly fine everywhere on the layout except the helix which, of course, is the most unusual track configuation anywhere on the layout.
So yes, I am seriously considering it.
I think there is an easier way if you have access. An old way to keep cars in a siding that has a slope is to mount a bristle between the rails strong enough that a train can bend it over but the car can’t. A series of these say every three inchs could be enough to stop a runaway. you will need to play with the distances to determine how close and how many will be needed. The one negative I see in advance is it will potentially increase the drag reducing the number of cars an engine(s) could pull up the hill
Use 2 prototypical solutions, first (as already mentioned), the runaway ramp, and/or you could install a derail. Use sensors and solenoids for high speed reaction times, but I’d program the sensors (somehow) for a time delay. That is, let’s say the sensors are 6" apart. If they trip less than, say, 2 seconds or so apart, then open up the derail or runaway ramp. This avoids forgetting to switch them off for the downhill trip. I’d DEFINATELY make sure to helix had proper guards inside and out to keep cars off the floor.
Brad
THen you just need to put another loco (or three) on point. Or maybe as helpers elsewhere…
I have just built the anti-rollback device that was featured in Nov 2001 MR (“Tortoise hill brake”), and it works great! (There’s a forum discussion here on it about a month or so ago.) Something like this would work on your helix. If it is a long or steep helix, consider segmenting it and installing one of the devices in each segment, to rise after the train passes while going uphill. Not required on downhill runs. Controls and sequencing sound like a royal pain to do… I like the idea of a pusher-loco that would add operating-fun. That way you get the advantage of a steeper helix too, using less space. In any case, the helix needs sides so nothing pops off to the floor. Have fun… George