Project 26 - Hewish Gates #8

To Part 1.

Project 26 - Hewish Gates #7

The display case was made from 1200 x 600 x 2mm Wickes Acrylic Sheet, cut with a Dremel and the panels glued together with Superglue. It is not fully dust proof as there is no rear acrylic panel or seals between it and the diorama.  At least it protects the model from finger poking damage.

I have in mind to make two improvements to the model, if I ever get around to doing so. 

The backscene should be professionally printed as one piece instead of the three I printed on A4 sheets. This will eliminate the joins and colour imbalance of the three sheets.

One of the level crossing gates takes on an angle when closed to the road. These gates were fabricated from two Airfix/Dapol level crossing sets (nothing wrong with that) long before I acquired a 3D resin printer. The resin printer now gives opportunity for a redesign to improve detail of the gates and their posts to represent the prototype more accurately and I'll take greater care in setting the gates uniformly.

To Part 8.

To Part 1.

Project 26 - Hewish Gates #5

As I laid down the vegetation it occurred to me that there are three scenes in this 52 cm x 37cm diorama, those being the level crossing, the signal box and the railway cottages. I assume the cottages were for two signalman who operated the box in shifts.

The double cottage is a Wills kit, The fence panels have been in my possession for possibly six decades. No idea of the brand.

The vegetation is a real hotchpotch of materials. Obviously, static grass layered for density and height with tufts being formed by first laying down anything that has a little bulk and then grassing over it.

The hedge next to the cottage is two layers of green kitchen scour pad covered in Woodland Scenics matting. Small shrubs are a strange fungus like growth cut from a dead branch and covered in minced dead autumn leaves and then spray painted green.

The larger shrub along the palisade fence line is dried moss from the garden centre sprinkled with the autumn leaves and spray painted.

The small tree is seafoam grown by myself and treated similarly.

Boundary fence in front is my own 3D printed posts with tinsel wire threaded through.

Note that anti-trespass sawtooth panels across the tracks next to a level crossing were not deployed at this location in the 1950-60s, judging from photographs.

To Part 6.

To Part 1.

 

Project 26 - Hewish Gates #4

I have reprinted the backscene that was created for the original layout (see Part 1). It is a photo of the real location printed over three sheets of A4. We can see from the hedging on the right how well the foreground merges with the background. The grassy bank on the left is waiting completion.

The downside is the join between sheets clearly visible and for some reason the shade of blue sky differs slightly between sheets. The only way to resolve all this is to have it professionally printed on one sheet.

To Part 5.

To Part 1.
 

Project 26 - Hewish Gates #3

How can a large hand wheel in the signal box cause four level crossing gates to open or close? It had me baffled until I researched the matter.

The hand wheel rotates a vertical shaft by means of bevelled gears. The bottom of the shaft in the signal box basement drives rack and pinion gears that connect to rods that move the gates via cranks in the same manner as turnout control. In addition road and rail side gate stop locks and wicket gate locks are controlled similarly.

At Hewish Gates in the 1930s the cranks and rods outside of the crossing area were covered by boards. By the 1950s the boarding appears to have been removed exposing the mechanics. I have modelled the boards in place to save modelling the mechanics. I only had to show rods where they cross the open track bed.

In the prototype there are more mechanics under the road surface that were accessed by removeable panels but most of the road was an asphalt covering over wooden boards, judging from photographs.

To Part 4.

To Part 1.

Project 26 - Hewish Gates #2

As usual, I made my own Code 75 flat bottom track, being not too happy with the Peco offering. Problem for me is their sleeper dimensions and spacing which may be more suited to H0 (3.5mm scale). My sleepers are resin 3D printed, originally designed by me for Graham Farish Formoway Code 100 flat bottom rail. Interestingly, Peco Code 100 rail did not fit but their Code 75 does perfectly.

I don't know if the Peco chairs are accurate to prototype but mine mimic UK BR1 chairs that were common in the 1960s.

As I only needed about 3 feet of track I bought the Peco SL100F and stripped off the sleepers to use only the rail.

With the rails covered for protection using drinking straws split down the middle; the sleepers were spray painted with brown/black acrylic. Rail sides and chairs were brush painted.

Ballast is my own mix comprising reclaimed and new material. In there to give variety of colour (does not show up well in the photo) are cork, coal, granite, pumice and maybe cat litter (not recommended) from earlier mixes, all ground and sifted to about 1mm length.

Ballast is fixed in place with diluted PVA remembering to add a few drops of washing up liquid to make it flow easily.

To Part 3.

To Part 1.

Project 26 - Hewish Gates

My original Hewish Gates layout was levelled to make way for my Battledown Flyover layout. I am feeling the loss of what was a delightful scene around the level crossing, particularly the merge of foreground to background, the latter being a photograph of the real location.

Hewish Gates was a compact scene on a larger layout. Whilst I don't have the room for another layout I decided to make a diorama of it that could be embedded in a larger layout if the opportunity arose.

Hewish Gates in reality is located on the main line west of Crewkerne in Somerset. Today it is simply a single track with barrier level crossing with all buildings gone. In its heyday the box not only controlled the level crossing but two main lines and  a long siding and loop west of the box.  

Having revisited the data I have of the prototype I noticed that I arranged the railway cottages to face the road whereas they should face the railway. That will be corrected as will some other anomalies.

For added interest I decided to make the level crossing operational and may add lights to the buildings and level crossing lamps.

First though, how to make the level crossing operational? All the tutorials I found on the web used servo motors and these require control electronics. I did not want this (which is a bit odd since I spent a large part of my career as an electronics designer). I preferred a simpler remote control by manual means. 

This exploded assembly is what I came up with. The principle is rack and pinion gears. The gates are connected to the four corner gears by rods.

At first I had just four gears, two each side, operated by one rack. Since the gates form a square (equal sides) all four gears mesh together except the two nearest the rack would not mesh!

Couple of points to understand for correct operation of the gates is the gears connected to the gates have to turn in opposite directions, which is why we need an even number of gears.

My second attempt was four gears as shown and plus two between them, set furthest from a single rack. Problem is this is not a precision gear design. Sloppy tolerances meant that the gates on one side did not turn a full 90 degrees.

The answer was two racks. Note that the racks need to work in opposite directions to get the gates to open symmetrically. It requires a push on one and a pull on the other. This could be achieved with one lever and another gear between rack rods. However, to avoid the complication and with fear of  mechanical tolerance problems I decided to drive the racks independently.

The rods are quite long, longer than the print bed of my FDM 3D printer which is why extension rods are used. 

Rack travel is limited in one direction by the protrusion on the racks that hit the frame and in the other direction by the rod couplings hitting brackets.

If this was ever embedded in a layout the rods would need to be controlled at the front or rear rather than the side needing a sliding mechanism instead of push pull.

 

This photo shows the size of the diorama and the level crossing location. I have used masking tape flags to represent the gates for testing purposes and yes the method does work.

To Part 2.