Point switching with 30psi compressed air to the system


This article may have been published elsewhere but cannot recall where but even so sadly it seems that this is now of historical interest only as "The Easy Air system" (E-Z Air, later renamed EA-ZE Air) is no longer in production finishing in about 2010.

I saw the heading of this article in Brandbright's advert in Garden Rail and thought now that is interesting. I have been in electronics as a hobby for over 20 years and did not like the idea of solenoids doing the switching of points due to fact the electricity and water do not mix well - if at all - so thought about a solid rod systems and then came upon the advert.

I checked out the web site of www.brandbright.co.uk who in 2007 had under the "Controls" section listed "Easy Air". It said "The Easy Air system" is a simple way of controlling points and signals. It utilizes air pressure to give superbly reliable operation under even the most adverse of conditions. The system is suitable on layouts from N scale through to G, both indoor and outdoor. A great advantage of the system is its ease of operation and installation. For garden operation, it is truly weatherproof and safe, the cylinders being manufactured from brass and rust proof stainless steel. No electrics are needed!"

I decided to immediately go ahead and order "EZ 710-2 Kit with 2 x 510 cylinders, air switches, pipe etc". I placed the order by email and then phoned through to give payment details. The goods arrived the next day; such is the service from this company.

The box is well packaged and all components were there including Two cylinder kits contain 2 cylinders, brackets and appropriate end fitting, 2 air switches, 50ft of tubing, a tee fitting and 1/8"NPT male to 1/16" barb fitting.

I was not familiar with the 1/8" NPT male but a search on the web revealed it to be 1/8" National Pipe Taper (U.S. Standard) Male thread to 1/16" barb fitting. Now this is fine in the USA but in UK and alternative fitting of 1/8" British Standard Pipe Taper Male thread fitting with a 1/16" barb outlet would have been easier to fit to my compressor. However more searching revealed that the thread difference between the two is very little and thus whilst it did not fit perfectly I was able to screw it a few turns into the compressor fitting.

So let's have a look at the basic parts of a system.

The piston

A well engineered piece of equipment which easily screws down along side the point to actuate it. Bending the brass wire is also easy but getting the exact place to bend is the part that takes time.

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The switch

Working out which pipe goes where took some time - bottom fitting in side fitting to actuator piston.

Tubing

The amazing thing about this tubing is that it slips onto the barb fitting easily and does not come off under pressure and to get it off without damaging the fitting you merely cut off the pipe! Ok so you loose about 10mm of pipe but it does make fitting and changing ones mine so easy.

The "T" fitting

Three barbs and used to join pipes where the pressure is equal and in my case is used to link the switch to the indicator and to the pipe leading to the point piston.

Compressor fitting

The fitting that goes into the compressor and then the outlet is connected to the pipe of the system

Compressor

Here is from where the whole system is driven.

Indicator

Whilst not in the basic kit I think is essential to show that the system has enough compressed air to operate. No indication then not enough air pressure

Next I wanted a quick test to see how things worked. A short length of pipe was cut and attached to the barb on the compressor, and this went to the switch and the other outlet of the switch when to the piston. On with the compressor and nothing happened. Changed round the connections on the switch and with the switch in one position out popped the piston, turn the switch the other way and the piston went back in forced there by an internal spring pressure in the piston.

Next I worked out a very simple arrangement to operate the point as can be seen in photo no.1.

The installation used up most of the 50 ft of pipe supplied in the first package. After operating the point successfully I thought how nice it would be to have an indicator that could be seen from the "signal box", in my case my workshop, that the point had actuated.

From photo no.2 you can see the simple arrangement so that the action of the piston operates not only the point but also the Ground Signal which moves from the horizontal to an angle. Now I may have the angle/colour wrong for the purists but for my railway is works just fine!!!!

Most of what is seen will be covered by a thin brass sheet cover to prevent as far as possible damage by the weather / gardening as my track is laid on ground level.

In photo no.3 you have some idea of what the arrangements looks like down the line.
With the success of the simple switching I decided to make more investment in parts to extend the system. I purchased:-

4 x packs of EZ 101K ADAPTER 10-32 thread to 1/16'' barb, black nylon, pack of five.

2 x of EZ 690 AIR INDICATOR Shows red when air pressure applied, panel mounted 1/16'' barb connection.

2 x packs of EZ 230K BARBED TEE Tee piece with 3 off 1/16'' barb connections, pack of 5

2 x packs of EZ 220K CONNECTOR 1/16'' barb to 1/16'' barb, used for connecting tubing. Pack of 5

I have also established that the 10-32 thread is UNF 10-32 and requires a 4.1mm tapping drill, so taps and dies were obtained so that I could make up items to be used with the system as for me part of the fun is the engineering. Still do not be put off thinking that you too have to make things, as the range of items that Brandbright have is extensive and thus you can buy rather than make.

With a total of 4 points on my line a further investment was needed for more of the pistons. With none of the standard ones available I took the underboard ones and adapted them very simply by soldering a piece of straight brass into the connector and in moments I had what was required.

As I progressed with setting up the system it became quite apparent that while a template of the support timber, does reduce the working out a bit each point on my line had its own peculiarity and thus in the end I decided to make each operator individual to the point.

To enable the operating of the system I decided to make a reservoir from a pop bottle - these are good for 100psi but you must test it hydraulically in the usual way and only use it for a short while as pop bottle are not intended to be cycle pressurised then released, as failure will almost certainly apply so after tests a proper pressure tank must be used.

So that the compressor is not operating all the time I build a pressure switch into a suitable box and set the pressure to 30 psi which I have found is quite sufficient to operate the points.

The display board is a very simple timber making job and I have included air indicators to show that pressure is in the line and also included a pressure gauge to check the local pressure. I will be adding legend to the board so that the switch is identified to the track location of the point

The inside of the panel is not very tidy but functional and will be tidied up in due course !!

With model engineering as part of my hobby I made the simple manifold that you can see in the inside control panel picture but these are listed as available from Brandbright.

With all the system in and working well now I will be turning my attention to signals - pneumatically operated of course !!!!

Basic kit 46. 75 from Brandbridght

Clarke Mini Air Compressor - Wiz 64.61 from Machine Mart

Additional part to make a great set up

50mm Pressure Gauge Base Entry 0-100 PSI AIR AND OIL 7.74 Harrier Fluid Power Ltd found on Ebay - so that you know what is going on - needs an adaptor " BSP (tapping drill 29/64") to 1/16" barb fitting

PRESSURE SWITCH TYPE GP600 29.77 M and M International UK Ltd found on Ebay - to shut off the little compressor as it is designed as a paint sprayer so would be manually turned on and off in short duration - so needs and adaptor 1/8" BSP (tapping drill 8.6mm).

An air pressure reservoir which was used initially was a standard "fizzy drink bottle" - suitably hydraulically tested to 80psi before use, which is 2x the working pressure (but they are designed to withstand 100psi), but this must be used at your own risk and a proper reservoir provided such as is on usually small compressors.

A manifold to link all the system together.

Please note prices are as at about 2007 and may have changed.

No responsibility can be accepted if you chose to use these ideas as you control the operating and thus must be wholly responsible for your and other persons safety.