Block instruments and bells

[Michael Hodgson]

I think that film is the reason modellers tend to believe that TPOs were classed as Royal trains (4-4-4 usually used for Is Line Clear for Royal Train?)  

4-4-4 was a local code used at certain stations such as Rugby for a through express not calling at the station.

[uax6]

The BR penguin block tapper (the only bit of the block left here in work - we're Track Circuit Block now) has a very definite click when you have made contact. The ones I hate the most are the Tyers ones where you push them in, there's no positiveness in their action. 

 

Andy G

[GWR57xx]

Progress has been lacking for the last few weeks because I've been waiting for supplies.

I ordered some electronics and some wood which have now arrived, but took six and five weeks respectively from time of ordering to delivery.

I think I now have everything I need to complete the build.

For the cases I decided to try using real wood for a change, rather than plywood or MDF, so I chose some Cherry:

 

The base is 18mm, the sides and top are 9mm.

I've cut all the pieces I need for two instruments and had a go at profiling the front edge of the base and top:

 

The burned appearance to the edge was caused (I think) by a little bit of oil that was on the router bit - first time I've used it, very pleased with the result. It's cleaned up nicely with a rub over with sandpaper.

The cherry cuts very cleanly and is a pleasure to work with.

Next step is to mark up and cut out all the various slots and channels so that the pieces positively locate with each other, and to hold the front and rear panels in place.

 

Edited February 11 by GWR57xx
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[Winander]

The burned appearance is not caused by oil but by the speed of the bit over the wood. I think its caused by moving the bit too slowly along the cut - I get it with a chopsaw and router. Unfortunately I am not experienced enough to know what the best cure is. I suggest you practice - it will be more prevalent when working with end grain. Be careful when sanding end grain as it is almost impossible not to roll over the edges, causing a small but annoying gap in your joint.

 

I like your choice of cherry and look forward to seeing more.

[Dave-5-5-7]

Here is my offering. I have gone for an IFS type panel. The layout is a loop with 4 track fiddle yard, and with a gradient leading to a yard. Eventually the line leading to the yard will go outside to a return loop so the diagram is functionally correct for both scenarios. 

The layout is split into three boxes. Moss Lane Signal box which is an IFS panel overseeing Saltfleet Town station, Theddlethorpe Junction and Mar Dyke TMD. Moss Lane works to Louth on Absolute Block, to Mablethorpe on a Train Describer and to Sutton Dock No. 2 via Tokenless Block. Sutton Dock No.2 is (will be) a mechanical frame. The instrument will be a wooden or ABS plastic box. 
Although not strictly an Eastern practice, it was this or Transient TCB, and the Tokenless Block instruments are more fun. At this end all block equipment is built into the panel. Louth & Mablethorpe are the fiddle yard, I'm hoping to find a suitable block instrument for the other end of Louth. 
The third "box" is a shunt frame which is a bit freelance. It's not BR and a bit more than a yard of manual points. 

Moss Lane IFS panel. 

 

Sutton Dock No. 2 Signal Box. 

 

ABP Sutton Dock Shunt panel (Formally No. 1 Signal Box). IFS 

Edited April 16, 2021 by Dave-5-5-7

[GWR57xx]

Some progress.

All the wood pieces have been machined:

 

A CNC router/milling machine would have come in very useful, but I had to do it with my little Proxxon and a drill stand. It coped very well, but a bit time-consuming.

 

Dry run trial fit just to make sure everything goes together properly:

 

And again with the acrylic and dibond panels fitted:

 

Next up is to cut various holes in the dibond panels to fit the servos, switches etc, and several coats of shellac on the wood.

Quite pleased so far 

 

[GWR57xx]

I've been thinking about the interconnecting cable between the two units.

I can think of a few different options, each involving a different number of conductors.

The fewest I think I can get away with is five: Common (Ground); Servo Signal A->B; Servo Signal B->A; Bell A->B & Bell B->A.

However, this version would depend on my servo driver board being able to drive the signal line over an extended distance, which I wasn't sure it could do.

So I ordered some servo connector sets to test the concept by breaking into the signal wire and inserting a 10m length of 0.5mm2 wire that was to hand.

I'm pleased to report that the test worked, so now I need to order some 5-way cable and connectors.

[GWR57xx]

On 16/05/2021 at 20:43, GWR57xx said:

 ... so now I need to order some 5-way cable and connectors.

Looking at options for these connectors I came across RJ12 which provides a 6-way cable in a neat package - basically telephone / network cable and comes ready made. Order placed.

[kevinlms]

On 19/05/2021 at 15:27, GWR57xx said:

Looking at options for these connectors I came across RJ12 which provides a 6-way cable in a neat package - basically telephone / network cable and comes ready made. Order placed.

You can buy a roll of cable and fittings and with the correct tool, make your own to your preferred length. People with DCC do this.

 

There are also network cables (patch cables) for computers, with what most people call RJ45 connectors. They are 8 conductor and are available in multiple lengths and colours. However while you can buy the parts to self-assemble, they are a pain to make and much easier to buy ready made.

[GWR57xx]

Long time no update for several reasons - life, work & covid getting in the way, plus some of the items I'd decided to use turned out to be hard to find and on long lead times.
When all the components had finally turned up I then realised that I hadn't really considered how much space they would need inside the instrument cases, so turns out it's all a really tight squeeze.
I've since spent a long time considering how to lay out the internals so that it would all fit and also so that I'd still be able to connect it all up while putting it together. Quite a 3D puzzle!

Anyway, finally some progress - these are the bits for one instrument:

 

 

 

Here it is all loosely assembled, just the tongue & groove panels holding it together:

 

There is also a "glass" (clear acrylic) panel to go in front of the needle dials.

 

It only just fits!

 

 

 

 

 

So then the big first test. 
I connected the RJ12 to the back panel then a "loopback" connector to the outside socket to route the tapper and command signal back to the bell and upper servo in this box.
Switch on - hmm, clearly not working properly, but at least the LED came on!
The servo control board just has some flickering LEDs where there should be just one solid light reflecting the position of the front 3-way switch.
Tapping the tapper does ring the bell, but the LED dims and the servos chatter.
Seems the 9V battery is simply not man enough for the job, so I'll have to reconsider how to power them.
After sleeping on the servo issue I had another look at the board and it turns out I had one of the jumpers in the wrong position. I took the jumper off and now the servos are working fine - phew!

Of course, now that I've found a way to cram it all into the case, the "obvious" alternative solution has occurred to me. Rather than having it all in the case I could have just had a separate control box to which both instruments were connected. That would have also made the power supply issue easier. Hindsight is wonderful!
 

Edited February 11 by GWR57xx
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[GWR57xx]

A couple of power supplies and associated power connectors have been delivered.

The first instrument has been fitted with a power connector on the back panel and the power switch suitably re-wired.

 

 

 

The photos also show the RJ12 loopback connector used for testing one box in isolation.

This box is now working as intended, so the next step is to repeat the mods for the second box and build it up.

 

Edited February 11 by GWR57xx
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[GWR57xx]

And then there were two...

 

 

Connected up with the short (3m) curly cord just for testing.

 

 

Don't you just love it when a plan comes together? 🙂

 

I've enjoyed making these, tried a few things that I've never done before and learned a lot.

But it's all just a bit of fun, which is what it was all about.

They've been quite a diversion from working on my layout, so I'd better blow the cobwebs off that and get on with it now...

 

Edited February 11 by GWR57xx
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[Jon Fitness]

Would love to see and hear a video of them in action

Jon F.

[D-A-T]

2 hours ago, Jon Fitness said:

Would love to see and hear a video of them in action

Jon F.

Slight thread drift but have you seen Barry Luck’s series of videos on YouTube about Block Instruments etc. It is exactly what I aspire to in my modelling.

https://youtu.be/ZhQtg3LH8oQ

[D-A-T]

 

[The Stationmaster]

16 hours ago, D-A-T said:

 

That is rather nice but I wonder why the Home Signals are being cleared before all the other stop signals or why the level  crossing gates are being closed before accepting a train?  Do the Home Signals carry out some sort of electrical function to allow control of trains departing from the fiddle yards (or whatever they are)?  Maybe the latter might be a consequence of using 2 position block instruments making more awkward to use the block to control power to track sections?

[Michael Hodgson]

1 hour ago, The Stationmaster said:

That is rather nice but I wonder why the Home Signals are being cleared before all the other stop signals or why the level  crossing gates are being closed before accepting a train?  Do the Home Signals carry out some sort of electrical function to allow control of trains departing from the fiddle yards (or whatever they are)?  Maybe the latter might be a consequence of using 2 position block instruments making more awkward to use the block to control power to track sections?

Yes, pulling only the Home lever doesn't comply with British Railways rule 39a (probably a different rule number in LB&SCR days).

 

First time I've seen 2-position blocks modelled.  They would have been used by the LB&SCR and were popular in early days on cost grounds despite their complexity.  This complexity was justified by only needing one line wire between adjacent signal boxes, rather than the 3 wires needed with more modern 3-position blocks .   The economics of model signalling are rather different, where wire is cheap and 3-position blocks are electrically and mechanically very much simpler.

[The Stationmaster]

40 minutes ago, Michael Hodgson said:

Yes, pulling only the Home lever doesn't comply with British Railways rule 39a (probably a different rule number in LB&SCR days).

 

First time I've seen 2-position blocks modelled.  They would have been used by the LB&SCR and were popular in early days on cost grounds despite their complexity.  This complexity was justified by only needing one line wire between adjacent signal boxes, rather than the 3 wires needed with more modern 3-position blocks .   The economics of model signalling are rather different, where wire is cheap and 3-position blocks are electrically and mechanically very much simpler.

Back in the period represented by the model it was Rule 40 in the RCH standard Rules and Clause a was exactly the same in effect as the later Rule 39(a).  Of course the fact that it was in the RCH standard Rules doesn't necessarily mean that the LBSCR used it in their Rule Book but as the rule made a lot of sense I couldn't readily think of a reason for not using it.

[GWR57xx]

On 01/02/2022 at 16:24, Jon Fitness said:

Would love to see and hear a video of them in action

Jon F.

 

Here you go 🙂: 

 

 

For some reason YT does not allow embedding of that video?

 

Edited February 11 by GWR57xx
fixed it!

[MickRalph]

On 02/02/2022 at 11:17, The Stationmaster said:

That is rather nice but I wonder why the Home Signals are being cleared before all the other stop signals or why the level  crossing gates are being closed before accepting a train?  Do the Home Signals carry out some sort of electrical function to allow control of trains departing from the fiddle yards (or whatever they are)?  Maybe the latter might be a consequence of using 2 position block instruments making more awkward to use the block to control power to track sections?

As one of Barry's operating team, I would point out that this is an exhibition layout, not full size, so that we have some constraints.  We have to keep a steady stream of trains moving to keep the public entertained; and the distance to the fiddleyards is a few feet, rather than several miles to the next signal box.  The layout (which is DC) is fully signalled, with full interlocking, and drivers drive away from themselves and must drive by the signals.  The home and distant signals are on not actually on the layout and are represented by LED lights on the control panel indicating to the driver whether either or both signals is pulled.

 

Clearly, there is no starter signal in the fiddleyard, so that when a train has been accepted by the Plumpton signalman, the indication that the train may leave the fiddleyard is pulling off the home signal (and the distant, if the train has been accepted by the other fiddleyard and the route is set all the way).  As the train enters the layout shortly after the lever for the home signal has been pulled, we c ould argue that Rule39(a) was observed; of course, pulling the signal is necessary to release the train from the fiddleyard.

 

As to closing the crossing gates to traffic before answering the bell code, this is necessay to avoid undue delay in the procession of trains through the layout.

 

Mick Ralph

[Jon Fitness]

On 03/02/2022 at 16:06, GWR57xx said:

 

Here you go  : 

 

 

For some reason YT does not allow embedding of that video?

 

Wow they're lovely! Well engineered and very attractive design tooMany thanks for the video.

[uax6]

The needles are a tad slow, they swing over quite quickly on the real things....

 

But nicely done!

 

Andy G