Air compressor for brakes?

[DianneB]

I am quite new to riding scale railroading but have already found the brakes on my LE American to be a poor way to stop. I have read quite a bit about all the different braking systems that have been used over the years and despite the cost and complexity I like the attributes of "automatic air brakes".

I have one difficulty - THE COMPRESSORS ARE NOISY! Or at least all the 12 volt compressors I have heard have been noisy. When you can identify which trains are using air brakes by the noise from 20 feet away, that just doesn't do it for me, especially with a steam locomotive.

Has anyone found a 12 volt compressor that is whisper quiet?

Thanks gang!

[rodw]

I don't know anything about model trains but I am in a 4WD club and I can assure you, there is no such thing as a quiet 12 volt compressor. Most of us have a compressor in our vehicles so we can adjust tyre pressures to suit the terrain.

The only suggestion I can make is to run an air tank. I run a 9 litre aluminium tank at 150 psi in my Toyota Hilux and a small regulator to bring it back to an operating pressure of 90 psi to run my air operated diff locks. Offroad in tough terrain, my compressor only runs about once a day. Just make sure the first 2' of air line is metal braided so it does not get hot and melt. After that, I run my air line using truck air brake line so it is possible to hide the a receiver tank in a carriage behind the locomotive.

Hope that gives you some ideas.

[redneckalbertan]

Has anyone found a 12 volt compressor that is whisper quiet?

Thanks gang!

Nope, every one that i have heard is noisy. But you might want to try rubber mounting the compressor so the car that it is in does not amplify the sound. Another thing you may want to try is placing something around the walls that enclose the compressor to help quiet it down, like Fiberglas insulation or styrofoam. Be careful the the compressor does not over heat up because of that.

[ccvstmr]

Dianne,

Like battery chargers, you get what you pay for. Better quality compressors will be "quieter", but that comes at a price. I doubt you'll find a whisper quiet compressor except by trial and error. Some other possible candidates include the following:

Viair (these can run $100-200 or more)
Harbor Freight used to sell a small, relatively quiet compressor (something like $25)
Campbell Hausfeld...portable 12 volt compressor package, but a lot better than the mini $8-15 compressors you find at Walmart/Kmart. I got a bunch of loose C-H compressors that I use for air brake systems.

You have choices. It just may take you some time to find a unit you'll be happy with. Carl B.

[cbrew]

this is the unit i have been using the last three years, it is the quietest one i have had to date.
its all rubber mounted.
i added a pressure switch and a couple small tanks, it recovers super fast so you don't have to listen to it for more then 10 to 15 secs at a time (only list you are pumping up the train for the first time)

for what your little engine will pull, you may want to look at building a small tank car from a portable tank and charge the tank at the steaming bay when needed

http://www.harborfreight.com/12-volt-15 ... 69285.html

http://www.harborfreight.com/catalogsea ... =air+tanks

[ken572]

I am quite new to riding scale railroading but have already found the brakes on my LE American to be a poor way to stop. I have read quite a bit about all the different braking systems that have been used over the years and despite the cost and complexity I like the attributes of "automatic air brakes".

I have one difficulty - THE COMPRESSORS ARE NOISY! Or at least all the 12 volt compressors I have heard have been noisy. When you can identify which trains are using air brakes by the noise from 20 feet away, that just doesn't do it for me, especially with a steam locomotive.

Has anyone found a 12 volt compressor that is whisper quiet?

Thanks gang!

Hi Dianne,
You will find that the only quiet air compressors are the one's
that are not turned on, or the ones that are inside of a sound
proofed cabinet, (usually fiberglass and foam lining). There
also has to be cool air vented through it. These cabinets can
get to be kind of bulky. If you have the space to build one and
fit it into your Loco, it might be worth a try.

If it were me, I think I would go hydraulic.
Junk yard parts
Clutch slave and master cylinder set up,
from a small car or truck etc.

Ken.

[DianneB]

I thought about hydraulic using water as a media but the problem of coupling and uncoupling cars without getting air bubbles in the system isn't easily fixed.

A good alternative would be using vacuum to hold brakes released but since I don't want an ejector hissing all the time, I will go with vacuum applied brakes.

Thanks for the comments gang!

[Harlock]

I have a compressor setup that is quiet.

Part of that is the compressor, part of it is the way I have set it up.

What you want is a Cadillac air ride suspension compressor, there are many of them on Ebay. here is one: http://www.ebay.com/itm/88-DEVILLE-AIR- ... 3a&vxp=mtr

The link above is closest to the one I have.

Couple it with a Square-D pressure switch and you are off and running.

The compressor sits right below my seat on the Chloe, yet I can barely feel it or hear it.

The secret is to give it a double isolation mount. The compressor is mounted to a heavy steel plate via small rubber isolation gaskets. The steel plate is mounted to the car by larger isolation gaskets. With that setup nearly all of the vibration is completely absorbed. The compressor is inside of a seat box which absorbs most of the sound. You do need to provide for some ventilation if you do enclose it completely or it can overheat on hot days.

The other secret is to use an air-tight system. By using all clippard barb fittings and bulkhead shutoffs and also putting a check valve between the compressor and the tank, you'll have a system that will hold air for weeks with the compressor off. In this way you can use a smaller battery and the compressor won't be running all the time. I charge the battery every couple of meets, it is a small tractor battery. It comes on only very occasionally. The switch cuts off at about 60 PSI and cuts in at about 45 PSI.

With good brake cylinders that do not leak, they use very little air. Air only leaves the system via the venting regulator that is the brake valve.

On the Chloe I use a clippard regulator (continuous variable pressure application) and on the MEG I use Jack Bodenmann's scale prototype brake valve (apply - set - lap - release etc. positions that work per prototype - more realistic)

It is the entire brake ecosystem that keeps your compressor quiet. Set it up as leak-free as possible and you won't hear the compressor much because it won't be running all the time. Use the double isolation mount system and you can put it under your seat and barely feel it / hear it when it is running. Or in a boxcar.

Many of the brake systems I have seen on various trains that I have run in the past have been extremely poorly thought out. This is evidenced by the fact that half the time they are not working for one reason or another. ("Just use the reverse"...) When I put together my two trains I swore I would not be one of those people. I like mountain railroading and I now have a very heavy train in 3" scale, the brakes are very important to me.

And for the record I do not personally have an interest in automatic / triple valve brakes. I use safety chains instead. I am not interested in this time in the added complexity of the fully automatic system. I feel that this is a personal choice and not a religious point of view, and that functionality can be added on top of anything I describe above.

I'll try to dig up pictures of my brake setups this evening and provide part numbers for the fittings. It seems there could be another Live Steam Magazine article in the works

The double isolation setup idea came from Jack Bodenmann. I operated Karl Hovanitz' SP Northern that Jack had laid his hands upon during the last rebuild, and a nearly silent air compressor was part of that setup.

Also, 'quiet' is subjective. Outdoors with the sounds of the track it is relatively very quiet. Your passengers will not hear it. You will hear it when standing still but while riding the rails it blends into the rest of the noise and I don't hear it most of the time.

-Mike

[DianneB]

Thanks Mike! Lots of good information there.

[Harlock]

Here are some pictures of the Chloe's riding tender. It is a MOW (maintenance of way) caboose, which generally consisted of a flat car with living quarters at the back half.

My incarnation of this item seats two, making it easy to train engineers. The footpegs on the car are for the higher rear seat, and fold in when not in use.

In the next post I will detail the innards.

[Harlock]

Here are general and close up views of the car with the seat box and caboose shell removed. The entire thing is built on a heavy steel Tom Bee flatcar which I modified quite a bit.

The original intent was to have a more traditional outside fence in the stake pockets with a smaller box in the middle to sit on, with a gap. But after all was said and done, the seat box grew to the sides of the car, 15" wide, in order to accommodate everything in it and the thickness of the wood box. You can see the cadillac compressor along with a square-D switch mounted on an arm that allows it to fit in the only available space left inside the seat.

Note the compressor's stock mounting connected to small isolation mounts, then to the 1/2" steel plate which then is connected to the large mounts. The mounts came from McMaster and they can be had in both male and female threaded versions. Unfortunately the exact model numbers are lost but I could measure them if desired.

Here is the page with the mounts:
http://www.mcmaster.com/#vibration-damp ... ts/=njfbz7

Also mounted to the pressure switch bracket is the shutoff switch, and another switch to turn on the caboose marker lamps. There is also a fuse which is vital in case something goes wrong with the compressor.

The orange camp fuel bottle behind the water tank is the reservoir. it doesn't need much. The fuel bottle idea was Tom Bee's, that's what I got with the brake kit. I would probably use a more traditional cylinder if starting from scratch.

[Harlock]

Here is the information for the clippard fittings, all 1/8" barb.

For between car connections, you want assembly # MQC-3S http://www.clippard.com/part/MQC-3S coupled with a package of barb adaptors for the inside ends, 11792-4-PKG. http://www.clippard.com/part/11792-4-PKG This gives you a bulkhead fitting with a shutoff, so when you unscrew the hose from the schrader style valve it keeps the air in if there is pressure on the car side. (unscrew the supply side of your connections first when breaking up the train)

The hose to be used with all of this is http://www.clippard.com/part/URH1-0804-BKS-050 don't buy hose from the hardware store. The hose is designed to work with the barbs and is generally softer than the cheap stuff. If you ever need to remove a hose from a barb fitting, heat it up with a small hand butane torch or wave it under a candle / lighter flame. Don't ever cut it because you will damage the barb. Cut off the heated part of the tube and discard.

A cutaway drawing of the MQC-3S is on this page of their catalog: http://www.clippard.com/downloads/PDF_D ... %20317.pdf

For a compressor check valve (between compressor output and resovoir) this should be the right one, coupled with two of the 11792 barb adaptors that will screw right into both ends. http://www.clippard.com/part/MCV-1BB

For tee fittings, use http://www.clippard.com/part/T44-4-PKG or for just one here: http://www.clippard.com/part/T44-4-BLK

For barb to NPT, there is a selection here: http://www.clippard.com/products/fitting-barb-npt

As a brake regulator in your cab, check out the MAR series of miniature regulators. This item with a custom handle is what I have on the Chloe: http://www.clippard.com/part/MAR-1-7 These are continuous venting regulators which give you a very smooth braking action. You can just move the knob for more or less braking power, no need to apply - lap - release etc. Practical for a smaller engine.

Complete list is here with different pressure ranges, just be sure to get the 10-32 ports to be compatible with your 11792 barb adaptors.

That should about cover it! When I first built that system, it would hold pressure for over a month with only a 1 or 2 PSI drop. After a while I think a hardware store NPT adaptor started leaking slightly so it only holds pressure for a few days now. For purposes of a live steam meet it is completely sealed and compressor use is minimal.

I have also made my own manifolds that mate with the 10-32 connections. The O-rings that come with the 10-32 adaptors seal up the connection completely, just have a nice clean mating surface on your manifold.