New, erm, old idea for brake van

[Keith S]

I have just ordered from IP engineering an Isle of Mann covered wagon (very excited) and an open-backed brake van.

I was thinking of an idea for the brake van: I believe it may originally have been "Irish Peter"'s idea and I have been thinking about it for quite a while now: a little centrifugal governor inside the brake van that applies brakes to keep the train from speeding down grades.

In my job I work with machines with tiny little governors, unlike the traditional Watts governor, they have little "L"-shaped weights that are very compact. There are adjustable "speeder springs" on top of them that vary the amount of spring pressure opposing the outward motion of the weights and therefore set the speed at which the governor acts.

I'm picturing something like this hidden inside the van, with an adjustment knob for the speeder spring under a hatch in the roof. It wouldn't be difficult to build with some bits of metal. I suppose the van would have to be quite heavy so that the engine wouldn't just drag it around with its wheels alternately locking and releasing.

I would need to think of some way to drive the governor from an axle, and of course make working brake gear under the wagon.

You'll probably wonder why I don't just put a radio control in the engine, it's because I am a stubborn luddite and I feel like batteries, wires, and bits of plastic on a steam engine takes away from its, (excuse the made-up word) "steamengine-ey-ness". I would have no problem putting radio gear on a little electric engine, absurdly. I'm relatively young yet and don't have much trouble bending over to open and close the regulator, but a bit of mechanical speed control in the brake van would be nice if it would work.

Does anyone have any opinions on whether this would work or not? I think it has a chance of succeeding if the brake shoes can be made not to bind and enough weight can be on the wheels so the brakes can apply some resistance to the train against the herculean pull of its Roundhouse power source

Well, even if it doesn't work, I can use the home made governor to demonstrate the functioning of flyweight governors to new guys at my work.

I'm excited about the new kits anyway, I find assembling IP kits to be cathartic: not very difficult but not boring either, and the resulting models are nice looking with my Roundhouse engine.

[JMORG]

It should work, its quite simple compared to the pneumatic brake systems I've seen!
I've never made a brake system, my engines arent really taxed with a heavy enough load to run away (They dont on our garden line, because its dead level)! The NGG16 usually has a big load but its so damn slow it doesnt matter.

I'm excited about the new kits anyway, I find assembling IP kits to be cathartic: not very difficult but not boring either, and the resulting models are nice looking with my Roundhouse engine.

They do look good, but then again he designed them for "Roundhouse scale".
All the best.

[Sir Clothem Cap]

if the speed the engine on the flat is the speed when the brakes are off then its logical and will work but the differculty is when the two ends oppose each other. If you go round a bend whilst they are opposing each other the train may be pulled off the raila in the middle.

But I do like the idea of a self regulating train so I say go for it. Lets see if it can work.

[Sir haydn]

These have been done before. There was one at butterley a few years ago in a 5 plank wagon, Problem was it didnt govern the speed very well as when the governor applied the brakes the loco just dragged the wagon.

[Keith S]

These have been done before. There was one at butterley a few years ago in a 5 plank wagon, Problem was it didnt govern the speed very well as when the governor applied the brakes the loco just dragged the wagon.

That's what I'm worried about. The wagon will have to be very heavy and maybe will have to be right behind the locomotive rather than at the rear of the train. Well, I'll give it a try when I get around to building the wagon.

[tom_tom_go]

There was an article of this in GR a while back of someone who had created a brake van with R/C servo braking.

I will have a look for it when I am off-shift and post details.

Cheers,

Tom

[sstjc]

Interestingly I aquired several old copies of SMT recently one of which has an article related to this. SMT 95, February 2001, Page 16 ' A Speed Regulating Vehicle'. Basically this is a van with a bevel gear on one axle driving a shaft which goes vertically up through the floor of the van. On the top of the shaft is a paddle or windvane which provides wind resistance the faster the wagon goes thus acting as a governor. Drop me a pm or make contact via 5inchrail and i'll scan it during the next week and email it across.

Barry
www.5inchrail.com

[GTB]

That's what I'm worried about. The wagon will have to be very heavy and maybe will have to be right behind the locomotive rather than at the rear of the train. Well, I'll give it a try when I get around to building the wagon.

It's 32C in the workshop and too hot to work, so I gave this some pondering time.


Once you lock the wheels, you can't get any more retardation from the brake van, except by making it heavier.

You then get into a never-ending spiral; you make the van heavier, so you need more throttle to get up the hill and the extra weight of the van will push harder downhill on a loco with a wider throttle opening........

Like the real railways, it works better with the braking spread out along the train and I think you'll need more than one vehicle to be brake fitted to have much effect.

The simplest way I came up with is to use the governor like a centrifugal brake. Fix the bob weights and their frame to the axle and let the outer casing (brake drum) rotate freely on the axle, then just use a tie rod between the outer casing and the underframe.

You could connect the casing to a crank on the brake rigging so you have a mechanical servo, but fitting full braking would be a lot more effort than a simple centrifugal brake on each axle.

I've been fitting working handbrakes to the batch of goods trucks I'm building, so they can be stopped from rolling away on less than level track. I did some measurements on the more or less completed brake van, which weighs about 600g and found that the rolling resistance is about 20g with the brakes off and about 200g with the wheels locked.

The other way to achieve what you want would be to fit the governor to the loco instead and connect the centrifugal servo to the throttle, with a return spring to open it again when the speed drops.........

Anyway have fun fiddling with it.

Regards,
Graeme

[Pretoria]

I've had a idea -- fit it on the engine !

You could turn the fly wheel into helicopter blades and (a la F1) arrange the blades the other way round to give more downforce the faster they go, hence more grip. Brilliant ! All problems solved.



(p.s. I voted for give it a try !)

[tom_tom_go]

There was an article of this in GR a while back of someone who had created a brake van with R/C servo braking.

 

It's in issue 201 using an Atropos covered van. The idea is the braking should be done next to the loco as if you have a brake van trying to brake right at the end of a train it will just create a bowstring effect and pull off other any light wagons between the loco and the guards van.

Cheers,

Tom

[sstjc]

I've finally managed to get to the scanner. It was hidden behind christmas. The implication from the attached article is that it worked ok for the builder.



I've sent a better quality image to those that requested it.

Barry
www.5inchrail.com

[DWR]

I went to york railway muesum and they had a model railway exibit on, one of the layouts was a gauge one, with a gwr slip coach, which had a motor which could be controlled but wouldnt go faster than what it was doing ad could stop the slip coach.

[TonyW]

I've had a  :idea:  idea -- fit it on the engine !

Years ago, a friend of mine had a Lady Anne with radio-controlled brakes built in to a tender. The servo basically pulled on a wire that was connected by pulleys to balsa wood brake blocks acting on the wheel running surfaces, just like The Real Thing. The tender was reasonably heavy and the brakes worked very well.

[Keith S]

I do have a tender on the engine which isn't really doing anything. I'm reluctant to modify it, though it is worth thinking about. Perhaps I'll test the mechanism on a wagon, then if it works, try it in the tender.