Servo driven level crossing (Lumsdonia Tip 804)

[TimberSurf]

Here is my design to move the gates of a Level Crossing
There are two designs, one for direct drive (I have called it Vertical) and the second is indirect (I have called it Horizontal) and is a little more low profile if space under the board is limited.
The Vertical design shown is for one servo per gate, but can be multiplied for two or four.
The horizontal design could be done with 2 or 4 servo's, but could equally be split into a tree of rods to drive all.

Supply list
Plastic Level Crossing gates
2mm diameter brass rod (or slightly larger)
Brass tube slightly larger in internal bore than the brass rod
Electrical (Choccy block) connectors
1mm Piano wire (or 0.8 or 1.2)
SG90 servo
Mounting screws (see text)
Servo bracket (see Note 1)
Araldite (two part epoxy)
Servo controller (see Note 2)

[TimberSurf]

Here are the pic's of the design for the vertical direct drive type

V Servo 3D front.jpg (40.62 KiB) Viewed 4302 times

V Servo 3D side.jpg (35.66 KiB) Viewed 4302 times

V Servo elevations.jpg (18.42 KiB) Viewed 4302 times

[TimberSurf]

Here are the pic's of the design for the horizontal indirect drive type

H. Servo 3D front.jpg (40.87 KiB) Viewed 4302 times

H Servo 3D side.jpg (39.17 KiB) Viewed 4302 times

H Servo elevations.jpg (18.02 KiB) Viewed 4302 times

[TimberSurf]

Instructions
Drill a hole up the gate post (grey)
Glue brass rod in (yellow)
Glue brass tube (red) into base board (brown), ensure it is at right angles in both directions
When set, drop the gate brass rod into tube with a plastic washer between to act as a bearing surface
Cut away plastic from one connector block to reveal the “two screw rod connector”
Attach to brass rod half way in, with one screw

Bend piano wire (silver) to fit in servo lever (see pic below)
Attach servo to servo bracket
Assemble linkage (silver) to servo and offer up under board, mark mounting holes and affix bracket to board
Make final connection to “two screw rod connector” (purple) in the other side


Note 1
The servo bracket can be bought from MERG (v. 690 or h.681) or wooden (laser cut ply) {Ebay have a few offerings} or Peco, etc.
You can make your own from sheet brass/aluminium or wood
Or design your own and print in 3D

Note 2
Servo control can be bought from the likes of Peco, Megapoints, MERG, Sometimes specific offerings from china on Ebay
Or make your own with 555 timer or arduino or raspberry.

For the Horizontal “two screw rod connector”, a (similar size to servo lever) strip of brass is required, with holes drilled in a row, soldered to the brass boss

Piano wire.jpg (7.68 KiB) Viewed 4301 times

[End2end]

2 quick questions if you wouldn't mind please Timbersurf.
1. What gate did you use?
2. How did you drill a perfect vertical hole in the gate post?
Thanks
End2end

[TimberSurf]

Hi E2E

I have not actually built one yet, but it is loosely similar to other designs I have seen, that have been built, it's just they tend to be finished products that make it hard for the inexperienced to envisage how it's constructed. Hence I did the design in CAD, so that it is more understandable to all.

1. Any make of gate would work, most have a protruding bar that locates in a layout hole, the metal rod could be drilled up that or direct in the post if it were cut off.

2. I could tell you to use a Vee block and set with a spirit level, set on flat surface, with drill similarly positioned opposite, or put in a four jaw truck of a lathe and centre with DTI, or scan with 3D laser alignment tool and set point cloud data into CNC milling machine, or just do it by eye!

If the eye method gets it slightly out of true, it does not matter as the brass bar is easy to bend to bring it in line. just make sure you start the hole in the centre, if it wanders off further in, a tweek with fingers or pliers will soon sort it out.

More importantly, it's imperative the (red) sleeve that it sits in, is at right angles (in two directions) to the surface of the layout. Best to glue the tube, with a plain rod in and support the rod with two square objects at right angles to each other) while it sets.

[End2end]

Ahh I thought you'd actually made one.
I have a picaxe board with red and green mimic panel LEDs all wired up ready to be installed when the time comes which will take feeds from a PM1 point motor.
When the point is thrown to the particular siding with the gate, the gate opens. When the point is thrown back the other way the gat closes.
Alas I don't know how to mount the servo and connect it properly to my gate using the vertical method.
I did consider if there was a vertical shaft you could mount directly onto the servo shaft instead of using a swing arm kind of attachment but didn't find anything useful sadly.
Without delving into boxes, Im almost sure mine is a Gaugemaster level crossing kit but the catalogue number escapes me.
I think the gate post has what I can only describe as an "insertion nipple" on the end to fit into the base of the kit and even though this nipple can be cut off the actual gatepost seems really small and hard to be able to drill into straight.
I'd need to check this though, as I did have a few gates before deciding on this one.
I wont be using the base part of the kit though as mentioned previously, this is for a private siding not a level crossing.
Thanks
End2end

[Ironduke]

How did you drill a perfect vertical hole in the gate post?

I think you'd need some kind of drill press and a vice. Or you could hand drill it very carefully with with a pin-vice.

I think I would include a spring in the mechanism somewhere so that the servo doesn't break anything if something stops the gate from swinging.

[Buggleskelly]

I started a project in 009, and made this crossing from a Dapol kit, and intended to insert it in a corresponding square hole in the baseboard. I used copper wire, running through a brass tube as a bush/bearing, to connect the servos and gates. And used a pinvice to drill the hole in the crossing gate post. I intended to operate the gates using an Arduino using just two push switches, but had no success in writing the programme for it, hence project scrapped and I have moved on. The vehicle on the crossing is a converted Dapol railbus using a Kato chassis.

IMG_20170707_093550 (Copy).jpg (54.43 KiB) Viewed 4072 times

IMG_20170707_092724 (Copy).jpg (25.31 KiB) Viewed 4072 times

[Ironduke]

That's a very small layout, Buggleskelly, but I like it. Is there a servo for each gate?

[Buggleskelly]

Yes, there is a servo for each gate, both mounted the same way. The screw holding the servo horn is directly beneath the gate post, and the cranked wire connecting gate to servo horn is just slipped through a hole in the horn. I found it worked fine, and at this scale I can't see any problems. There are probably many ways to make a connection to the servo, and had thought of silicon tubing between servo and gate rods to provide a sort of friction clutch in case of gate jamming, again at this scale n/009 that would probably work too.

[TimberSurf]

For those with a dilemma over driving the servo with home made/programmed (picaxe, rasberry, arduino, PC, etc.), there are several ready made circuits available like:-

http://www.blocksignalling.co.uk/index. ... riers-lcs5
https://www.heathcote-electronics.co.uk ... ssing.html

You could even build your own with a 555 timer circuit, but the easiest and cheapest for instant gratification, is to use a servo tester, most hobby shops have them or wait 6 weeks from china and much cheaper.

servo tester.jpg (16.83 KiB) Viewed 4054 times

There are even, ready made gates!
https://www.heathcote-electronics.co.uk ... gates.html

[End2end]

After digging my kit out I can confirm it is a Gaugemaster Fordhampton level crossing kit GM404.
The gates end uprights are extremely small. This is the best online picture I could find of it "on sprue".

You can see on the left end of the gates the problem.
Unfortunatly I don't have the tools mentioned to drill an accurate hole in something so small.
Thanks
End2end

[Ironduke]

I sense a lack of determination there End2end. A pin vice is a very useful tool to own, along with a set of very small drill bits. But with that kit you might be better off just replacing that end of the gate with a longer piece of rod the same size. Or try moving the gate some other way. Are they usually closed by a person in real life?

[Tricky Dicky]

Hi E2E

One way of attaching a wire to the gate without any drilling is to use a short length of brass tube that is a push on fit onto the hinge pin on the gate. Many of the brass tubes available in model shops are designed to fit into each other, so using ever decreasing diameters super glued to each other the hole will reduce in diameter until you can secure the wire you desire. You will have to drill out the pin holes in the bases to suit the tube diameter.

Richard