Tenbione Jn. Signalbox

[SHMD]

Tenbione, (my current layout build), needs a system to control the points and signals...
 
...and what could be better, than a working Signalbox, to move the points and set signals!
 
 
So to operate my layout I am going to build a Signalbox to not just set the signals and change the points, it's also going to set the frog polarities and the isolation sections too. (Initially, the layout will be DC but it will/is DCC compatible too.)

So, once the trains are given the OFF the trains will then drive themselves, to the signals, along the set route to the destination.

Other modes of operation will also be allowed including" Box locked out", "automatic control", "timetables", "manual override", "free range", "diagnostics", "possessions" and anything else I can think of!

 

I have been building up to this project (for years) by testing various aspects of the design on smaller mini projects including :- "Smart Driver Board", "A Ground Frame for a Plank", "Ashton Rd." to prove viability.

There is plenty to do, not just in construction, design and software, and learning "signalling" but also in knowing where to pitch the many compromises I already know are required.

 

Today, I am pleased to announce, that I am satisfied that I can "do this" and so have now "officially" started!

 

 
Kev.

[SHMD]

Tenbione Jn. will be a 40 lever frame box with a level crossing wheel.

 

The frame won't be mechanical but instead it will be electronic with the emphasis being on minimal wiring.

 

Although the design is electronic, with very little wiring, there is the built in facility to electrically interlock any lever by wiring it to external devices or even other levers. I don't plan on using this feature - at least initially.

 

The "brains in the box" is a Pic Micro Controller - the Pic18F4550 mounted on my own Accessory Control Board "ACB1" pcb which gives 32k ROM, 2k RAM, 256 EEPROM, 3x8bit industry standard ports, 1xUSB port, 1xSerial port, and 1xI2C port. The ACB1 board has proven to be a very versatile and robust piece of it.

 

Connected to the ACB1 cpu will be...

...the Extendable Toggle Board "ETB1".

 

Here is the schematic. Basically, this circuit has 8 toggle switches - which are biased with resisters - that go into an 11 channel serial ADC.

 

This is the CAD pcb..

 

This is the pcb..

 

The 3D simulation of the circuit is great for checking clearances and board aesthetics..

 

This view gives a hint of what the lever frame will finally look like..

 

 

I told you there was a lot of electronics involved!

 

 

Kev.

 

[SHMD]

Other boards will be a mixture of commercial circuits and my own.

 

 

The commercial circuits are mainly displays like a 4x20 LCD, keypad, 7segment displays, etc..

Boards from my own stable include the ...

 

Human Interface Board "HIB1"

An 8 channel board that can have any combination of Bi Colour LEDs or tactile Push Buttons. These LEDs/PBs can even be mounted on either side.

That's two off of the same HIB1 board but configured differently.

 

 

I plan on having 5 or 6 of these boards, in the Box, but the ACB1 cpu only has 3 available ports. Thus, an I/O Expander board was required...

 

The schematic for the Input/Output Expander board "IOE"...

(This circuit is pretty standard and held no surprises!)

 

pcb CAD file.

 

Both the schematic, and PCB layout software, are the excellent freeware Diptrace from Novarm.

(Usual disclaimer and not even a customer, just a very happy user.)

 

Again, the 3D modelling helps to get the PCB footprint down to the minimum size possible. (For through hole components.)

 

Four boards just off the production line.

 

..and just about to be tested.

The IOE board in the test setup is actually the prototype where I tested things such as noise immunity, bandwidth, power-on-resets, software (bit-banging) I2C comms, and Hardware I2C comms.

 

I found that if using a hardware I2C comms master, to this board, then I had to have the power-on-reset Capacitor (C4) removed.

 

 

Next up is the Extendable Toggle Board "ETB1".

 

 

Kev.

 

[SHMD]

I've already done ETB1 !

 

Anyway workbench, Laptop, reference books, and some prototype testing being undertaken.

 

 

So these are the required boards (so far) to make Tenbione Jn. Signalbox tick.

I have laid them out in roughly the way that they will be positioned inside the Box, although the ACB1 cpu will be housed downstairs.

The five bottom boards are the ETB1s which will give 40 lever input positions.

The HIB1 boards, above them, will all be bi-coloured LEDs, positioned above their respective levers, on the instruments shelf.

I'm going to use the Stirling Engine's wheel as the wheel to operate the level crossing gates.

The cabin will be approximately two and a half feet long.

 

The ETB1s being tested..

Note that the toggle levers themselves have not been fitted yet as I have to allocate the lever functions (and colours) and so some leveres will be ON-ON and some (not many) will be ON-OFF-ON switches.

 

..and all most of the boards built and tested.

 

 

Wiring up 40 levers anyone?

Simplicity itself. Just daisy chain a 10-way ribbon cable from board to board back to the cpu. Job done!

 

 

Kev.

 

[imt]

With an absence of Christmas spirit I suppose and with great respect, and some trepidation, might I say I think I should be impressed but sadly I am not.  If I had even the vaguest idea of what you were doing and why, I might be able to see some relevance.  At the moment it is a load of (no doubt excellent) DIY electronics strung together for some unknown and unfathomable purpose which I cannot buy, see or touch even if I wanted/needed some of it.

[dajt]

Looks like a great project! I like a bit of electronics with my trains.

[SHMD]

With an absence of Christmas spirit I suppose and with great respect, and some trepidation, might I say I think I should be impressed but sadly I am not.  If I had even the vaguest idea of what you were doing and why, I might be able to see some relevance.  At the moment it is a load of (no doubt excellent) DIY electronics strung together for some unknown and unfathomable purpose which I cannot buy, see or touch even if I wanted/needed some of it.

 

Hi imt,

 

No need for any "trepidation", I am not going to bite! And you are right about inferring that there is a lot of electronics here - there is!

But I had thought that I had made it quite clear that I am making a working signalbox to operate my layout with. I refer you to the first three lines in the first post of this thread.

 

Actually, most of the "electronics" is now out of the way - although there is a lot of software development to come.

The next stage of the signalbox build now starts with the scratch building of the signalbox structure itself - I hope you stick around for that.

 

 

Kev.

[SHMD]

The cabin will not be an authentic scale model of a particular signalbox as, whilst I want it to look and feel like a signalbox, I really want it to be a working control system for my layout.

Having said that, the signalbox will be either LNWR or L&Y based - possibly even a mixture of both as I like the outside look of the LNWR boxes and the inside look of the L&Y ones! Is there a prototype for this? There must be.

 

I intend to have an all wooden signalbox as I have not done any brickwork in 5" scale (yet).

 

 

Kev.

 

[SHMD]

I've decided to build an LNWR Standard Type 4 all timber Signal Cabin.

This will be of size H which is 26' 6" long and has a 2 + 3 + 3 + 2 window arrangement.

 

Today's CAD work has produced the following front elevation.

 

 

Kev.

 

[SHMD]

Yesterday it took all day to produce the CAD for the Front Elevation. Today it took less than an hour to produce an End Elevation.

 

These views do not show any iron work, gutters, down spouts or 100 years of modifications!

 

Also, I am not sure if the (none stairs end) should have a 2 frame window (as shown above) or a 3 frame window?

The stairs end will only be a 2 frame window to allow room for the door and the lav.

 

 

Kev.

 

[SHMD]

..and now for the stair end elevation.

 

(Minus stairs and lav.)

 

 

Kev.

 

[SHMD]

More CAD and some wooden mock-ups.

 

This is getting complicated..

 

These dimensions are the nearest mm of the feet and inches of the original divided by 11.3 (5" gauge).

This keeps the proportions of the prototype but, unless I make my own stripwood, these sizes are just not available.

 

 

Now for some mock ups of the base using metric stripwood from BnQ.

This is 715mm x 324mm!

 

More stuff added but nothing set in place yet.

(This is going to take a LOT of wood.)

 

A view of the joists under the lower floor.

 

just a check to make sure that the 40 levers and the crossing wheel will fit in the cabin.

 

 

Kev.

 

[Vanders]

I am nothing but impressed. I'd love to see an article(s) on this; I'm sure MERG would be more than interested!

[SHMD]

I started with proving the control system and then I drew up some Signal Box plans by dividing the reference books feet and inches by 11.3, the results looked good.

 

First the Front Elevation was drawn and then the two End Elevations.

Finally the foundations were laid out - and this is where the trouble started. What pitch, and where, should the joists go? Now add in the "Frame Uprights " and then, using the Standard Lever sizes made. Finally divide by 11.3 and translate to the nearest metric stripwood sizes. Now (!) does it still look good?

This has taken a week, and I am very glad that I haven't used any glue yet as I have made SOOOooo many changes!

 

So, starting again from the foundations up - using readily available metric strip wood sizes.

 

The under floor Locking room joist spacing view has taken a lot of thought and time before I am almost satisfied.

 

..after that the cut away detail views were easy.

 

 

Some mock-ups where I try out ideas..

 

Levers and wheel positions and spacing feasibility study..

 

The walls should be vertical internal framing with inside and out horizontal planks resulting in an overall thickness of 6inches. I am just going to 15mm thickness strip wood as no one will know is the internal baton-ing is there or not!

 

 

The Lever PCBs should be mounted, at an angle, Just below the ceiling of the Locking room. The Level Crossing Wheel will be in the Signal Cabin above the Locking room.

 

..an idea of what the levers (not actually shown) spacing will look like.

 

 

Kev.

 

[MarshLane]

Hi Kev,

Interesting concept! Shall be following your progress ... and hopefully progressing with mine!

 

Rich

[SHMD]

Time for thinking...

 

 

Here is the layout plan. "Tenbione" is a ten foot by one foot layout made on three base boards.

The " Road Overbridge" is to be a new build replacing the (now) redundant level crossing. (But I still want the SignalBox wheel to still work.)

 

(If PECO come out with a single slip, to then new/better sleeper spacing, then a whole new track plan will be required for the central "senic" section.

 

The use of the Hornby MKII coaches is to check that the "trains" will fit as each fiddle yard siding will be 2xCoachs in length - or 2 SLUs (SLU = Standard Length Unit or a coach {or better still, a class 40}).

Sadly, long trains will not be a feature of this layout....   

...but high intensity operation will be   

 

Looks innocent enough but...

 

...lurking beneath the baseboard is the wiring - all ready for manual, computer or even Signal Box control!

The wiring is simple - no really it is.

The longitude blue a brown wiring are the track "bus bars". The thick red wires are SEEP point motor wiring - all one to one wiring and each less than 200mm in length. The rail droppers are either fed from the bus bars (permanent) or one of the three relay boards (switched). The last (few) wires are inter-board comms.

 

Simples!

 

 

 

Now for the next thinking bit....

 

..the lever assignments and colours!

 

 

Kev.

 

[SHMD]

Tenbione was, and is, going to be computer controlled. (This SignalBox build is just another distraction on this layout!)

To do this, I needed to "signal" the layout to control it. ie - I had to, in effect, assign levers to signals, points and "other" items. The other items being isolation section, controller selection, Frog polarity, etc.

I tried to stay true to prototype and some compromises came to light. eg. Isolation sections being ground signals!

 

In effect I had to build a virtual signalbox to computer control it.

Soooooo - why not build a real (manual) signal box that would allow me to test / run the layout before the "computer" is ready?

 

 

Here was my initial lever plan. One for a 32 lever frame.

There are a couple of spares but I thought it was "tight" as (with me) you always need more than you first thought!

 

 

Also, points 9, 10, 11, 12 can be rationalised into (in effect) 2 cross overs - 9a & 9b - operated from lever 9, and 10a & 10b - operated from lever 10. Thus free-ing up levers 11 and 12.

Now this initial plan, was for a 32 lever frame, with 2 spares (plus 2 more), may seem enough but I now need to add the level-crossing so I think I will stick with the 40 levers (minus a couple as the Webb Tumbler Frame had gaps where the Frame-Uprights went).

 

 

...I need to work on this...

 

 

 

Kev.

 

[Junctionmad]

I am nothing but impressed. I'd love to see an article(s) on this; I'm sure MERG would be more than interested!

 

MERG has can bus  IO coming out its ears !

[SHMD]

MERG has can bus  IO coming out its ears !

 

Agreed. (Although I have no idea if Merg has io coming out of its' ears or not) but CAN bus should be far more suited to the model railway (electrical) environment than I2C is.

 

 

Kev.

[Junctionmad]

Agreed. (Although I have no idea if Merg has io coming out of its' ears or not) but CAN bus should be far more suited to the model railway (electrical) environment than I2C is.

 

 

Kev.

 

just that MERG has a whole series of  can bus connected IO boards, just the thing for a signal box system.  It also has  conditional logic modules and things like a Raspberry Pi interfaces to facilitate locking and layout automation 

[Junctionmad]

personally if I was going to all this bother , ( and I sort of am ) , I would use a proper  lever frame wired with micro-switches

[MarshLane]

Kev,

Have you thought of taking the isolation out of the frame? Using detection, you can establish if the full road is clear and switch both sections on when you clear the route. If detection shows that there is a loco stood in the isolation section, you can use logic to decide what is electrified. When it comes to Signalling trains out, again detection decides what is switched on.

 

You could always use an on-off button as an electrical lever release to override the electronics and power the full siding...

 

Rich

[SHMD]

Mornin' Rich,

 

The isolated sections, on the layout, are an integral part of the control scheme. They're there to :-

 

keep DC locos still,

sense stock passing over/onto/into them,

allow a free mix of DC and DCC stock to run/stay anywhere on the layout,

part of the "dead-reckoning" system for automatic trains.

 

 

Kev.

[Junctionmad]

Kev,

Have you thought of taking the isolation out of the frame? Using detection, you can establish if the full road is clear and switch both sections on when you clear the route. If detection shows that there is a loco stood in the isolation section, you can use logic to decide what is electrified. When it comes to Signalling trains out, again detection decides what is switched on.

 

You could always use an on-off button as an electrical lever release to override the electronics and power the full siding...

 

Rich

 

detection is fraught with issues , what happens when propelling , the loco mightn't even be in the relevant detection block even as the wagon passes a signal at red !. Aldo unless you do resistor wheel sets etc , you cant sense stock etc,  

[SHMD]

All agreed but...

 

Tenbione is operationally simple.
I want a big operationally complex layout but I don't have the space or time to do that. So I have to make it interesting in other ways.

Normally, I just want to watch the trains go by as I sit and think. I can’t have a roundy-roundy and even then I would want different (or even random (unknown)) trains to come along at different times. Sometimes I want to be fully involved and true to prototype – other times I just want to move things by throwing the rule book out of the window as I see fit!

 

 

I was DC.
Then DCC came along and I jumped at it instantly.

But I soon realised that I had “lost control”.
Sure, my Lenz 100 moved trains brilliantly as I turned the knob, addressed a particular loco and actually “drove the train rather than the track”, and I could do new tricks too, such as moving 2 locos differently in the same section (without isolation tracks and with the freedom to do this anywhere. I soon dispelled with the wiring fallacy though – wiring can be simpler but the precautions can be more complex). The sound is stunning too.
But...

 

But I couldn't control “Lenz” at the electrical/electronic/firmware level.

I couldn't stop/slow/reverse/pause a train/loco automatically. - In short I couldn't do it “my way”.
Will the signal man hold a red flag out of the window and the driver stop (this time) as he passes the  signalbox? Temporary speed restrictions. Driver “personality”, making up time, etc!!
Sure proprietary solutions are available for some of these but with restrictions – fixed positions for example.

I have now moved back to DC. As I can control the loco now.
I like DCC – especially the sound. (But not the lighting – 1970s BR signals, locos and tail lamps can be very accurately approximated to very very dark dull! Which can be very accurately approximated to not lit in the first place!)
Even though I have designed, built and run my own DCC controller. (I won't get involved in the arms race that is the decoder market! Decoders are way better than what I could come up with – especially at that price! - and I can not see surface-mount components to solder them!) I have found that I (I as in me via my controller) am in more control of the trains movement then when I do this via DCC.

My way I can do anything I want.

 

Besides, I like designing schematics and PCBs.  

 

Kev.