The club's O gauge layout (Castle Morris) had had a a small extension built and fitted at the terminus end, as an extension to serve a small agricultural wholesale company with a small private siding. This siding is an extension to the running line into the terminus through a level crossing.
The level crossing is a kit from MSE (Code LC7 single track crossing). It was originally fitted as a non-operational scenic addition. Someone (could have been the club chairman, I know not) suggested that the level crossing should be operational by the time it appeared at Model Rail 2020 Glasgow.
I think I "volunteered" to do the work as I was already working on installing some signals on the same layout (in time for the Glesga show).
Anyway, here's how I processed this task.
First thing was that, as it was a single track level crossing, operation needed to be fool-proof.
Operation to use servos.
OK, I know that there is a system already available to drive a single track level crossing available.
But, as I was already working installing signals using MERG Servo4 kit (with bouncing facilities), I thought I could use the same MERG item for the level crossing (using 2 servos, one for each gate).
OK. First things first. How to operate the gates. Gate 1 opens, then gate 2 opens. The main thing was to avoid the gates clashing in the middle of their operation.
A colleague at the club came up with the answer using 3 microswitches.
Take a bow Colin Walker.
Colin's plan:
Now to put it all in practice.
Something was needed to locate the servos, microswitches, control board, etc. This base and the two 90° horns were designed using Autodesk Fusion 360 and 3D printed using ABS filament.
The Level Crossing had already been completed and installed on the layout. Thankfully, the gates were able to swing so hadn't been glued in place. The gates were removed.
The holes in the upright posts (with the servos at P) were drilled out to take a brass tube as a bearing for the gate operating rods. This tube is the full length from where the right angled horn sits to the base of the gate pivot post (which includes the thickness of the baseboard). To operate the gates, I used a length of stiff brass wire, about 1mm diameter. The gate posts were drilled out to accomodate this wire. I drilled to a depth of 4mm and then cut a slot, the same length, up the side of the gate pivot post (to prevent the wire spinning inside the post, which did happen at first despite glueing).
A small 90°bend, about 2mm from the end of the wire was formed and this was epoxied into the slot. When all set, the excess wire was trimmed back flush with the post.
The base was located and screwed under the baseboard, the brasss tubes locating where the gates would pivot. The servos and microswithes were already in place, along with the the MERG Servo 4 controller.
From the topside, the wires in the gates are fed through the brass tube bearings. The gates are fixed in place using the top hinge which locates on the top of the gate pivot post with a small length of brass wire as a pivot.
Working from underneath again, and this is where it become a little awkward, making sure the gates are in the Road Closed/Rail open position the 90° cranks are slipped over the protruding pivot wires which are bent over at 90° to align with the gates above the board.
Using the controller the servos are initially set at 45° (as in the picture above).
(NB In the above illustration, the servo operating at the side with two microswitches is set correctly, the other servo is incorrectly positioned for startup).
Fitting an operating link (I use piano wire of suitable diameter) between the 90° crank and the servo horn, the servo should be set to operate through 90°. This will open one microswith and close the other at the end of the sweep. The other servo will only operate one microswith, but will still move the gate through 90°.
To locate the bent wire correctly, I designed a small filler part that fitted inside the 90° cranks, bending the wire again locating into a small hole.
I think that that's just about it.
Oh, I did fit a small red LED inside the lampholder on the gates, fed through very fine twin enamelled wires, routed along the gate top rail and down the pivot post, connected to an existing 12V DC supply via a suitable resistor.
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