Steve Hewitt

Will, The delay between the route being set and the signals clearing serves two main purposes: 1. To simulate the time taken by the signal man in the box moving from lever to lever. The delay is a random period of some 5 to 8 seconds, and also applies between clearing the Starter and Advanced Starter signals. 2. The delay also allows the operator to use his "Signal Inhibit" button to prevent the signal clearing until the Inhibit button is pressed a second time. This is used for example to allow an engine to be moved along a platform from the Buffer up to the Starter signal, or to hold an inbound train at the Gantry in the Cutting. In these cases, the move would be complete when the engine or train was stationary at the signal, and the Cancel button would then be used to leave it there without the signal having been cleared at all. I think Michael has answered the question about the Cancel button quite well. Thanks Mike. As for Route Interlocking, John has sent me the following quote: "The software does incorporate route interlocking between the two operator positions. The reset button only clears it's respective route, leaving any other route untouched. As well as route interlocking, we have route proving, and route routining within the software, the route routining only being done on initial power up when the layout is first set up at a show, to prove all interboard connections are correct, and all points are responding." The two turntables and the sector plate are controlled with extreme accuracy by "Stepper Motor" technology. Geoff Peters who makes all the control technology for the layout now markets the turntable controller, and the servo controller for semaphore signals as a commercial activity. He has set up G F Controls with his friend Frank, and details of these products can be seen at: http://www.gfcontrols.co.uk/index.php/news/ Steve.

Some recent posts have mentioned the "wiring" underneath Lime Street's boards, and Mike's recent pictures of some of the trackwork made by Chris Hewitt have prompted me to try to describe how the layout is actually controlled, and the the technology that has been used to create the control system. The principles are basic DC control. There are three controllers, two for the Station area and one for the Sector Plate/Storage Sidings. Traction current is applied to the track only in the sections necessary for the selected routes. A route is selected on the control panel using two push buttons on a geographic display. The laft side of the Station Control Panel The right hand side of the Station Control Panel This is the Sector Plate/Storage control panel. The first button pressed is the "from" location, the second is the "to" location. A number of actions follow, each determined by the main process controller: 1. The route selected must be a valid route. (there are some 220 possible routes in the Station area) 2. The route selected must not conflict with any other route already set. 3. All the points along the route are set. The movement of each Fulgurex point machine is controlled by its own relay, which will be "normal" or "reversed". 4. Changeover contacts on each point machine complete a circuit which logically represents the route. When this circuit is complete, it indicates that each point machine has moved correctly, and confirms the route. 5, Separate relays connect traction current from the operator's controller to each finite element of the set route. These can be very small elements of track, only a few centimetres long in complex areas of pointwork. 6. Mini LEDs illuminate the route on the control panel. 7. After a few seconds delay, the necessary signals along the route are cleared. 8. The signal aspect is repeated on the control panel Any error occuring during the above will halt the process and sound an alarm. e.g If a point machine didn't move, or the route conflicted with one already set. After the move is completed, the operator hits the "cancel" button and is ready to give his next command. This releases all the routes resources to be used for a subsequent command. So, what does this look like in reality: Here is photo of the underside of "board 8". This is the board supporting the platform exits on the South side of the station, and the entrance to the turntable area. You can see the array of relays for this base board to the top right. The circuit board to its left contains the servo controllers for all the signals on the South side - 16 in number. This is one of the point machines in-situ. The mechanical connection to the operating crank for the point. The corresponding crank "above ground" A close-up of the relay array. For ease of maintenance, all the point machines are installed in a uniform way. Here is a "spare" ready to be installed: Finally, a close up of the Servo Control board, which we are currently commissioning. None of the servos have yet been connected to this board. I'll take a breather here, and post some details of the two main processers etc. later. Steve.

Mike, The text gives some very interesting details on "Running In" turns to and from Lime Street which we can buld into our operating schedule. Steve.

All the plywood was 9mm thick. Steve.

Sorry for the delay in getting back to you. The short answer is "No". On the day the pictures were taken, John, Les and I had a chat about the design of the box needed for the North Roof. (The box for the South Roof had been made last year). A copy of the same design would have made the North box too large and heavy. We discussed the idea of saving space by having roof sections "overlapping" vertically, and reducing weight by making the shelves more skeletal. Geoff later advised John about the Double Extension drawer runners, which allow each roof section to be pulled out fully from the box. Instead of a full drawer base, John chose to use a rigid plastic angle section to support the Roof assemblies, saving a lot of weight. With these basic design ideas sorted out, John then acquired the necessary materials and built the Box to fit the roof sections, making the detail size and assembly decisions as he went along. Steve.

Here are the two storage/transport boxes with the roofs in place. The smaller roof - South - is actually in the larger box - 860mm wide x 600mm deep x 780mm high The larger - North - roof is located on shelf runners in its box which is 800 W x 800 H x 600 D. This allows two sections to slide within the arch space of the others, saving height. John tells me "I intend to make a "locating frame", that will sit on top of one box, and allow the second box to sit on top of that without sliding off during transit in the van. Each shelf is customised with wooden stops that hold the intended roof section in place without "sliding about" when handling the box. Details of the orientation of each roof panel is provided with the labelling on each shelf. Both boxes have yet to be varnished. This will be done prior to our next show." Safe storage for the roofs means we can now dismantle the main boards to enable the next series of upgrades to be be realised. Once these are completed, in the next couple of weeks, we will be ready to start serious training for the Ally Pally show in March. We are optimistic that the work we've done since our trip to Utracht will give us another sizable step forwards. Steve.

Mike, You won't have to wait so long. Once the current upgrades are completed, John will be holding regular running sessions for the Ally Pally team, to ensure we put on a good show. Steve.

Thanks Mike, and Happy New Year to you. John has spent time making the transport box for the new roof, and once its available we will be dismantling the main boards once again to install the second part of the signal control system (Platforms 6 to 11, plus the turntable release). Geoff has spent the Christmas period making the necessary boards, and including some new features in the control panels, which we hope to commission in the next couple of weeks. Whilst we are doing that, I'll try to photograph the main parts of the control system and then we can write it up on RMweb. Steve.

Alley Pally in March is our next outing. Steve.

I was pleased to be at John's when Les took the pictures. I think you'll agree they are worth waiting for................... Steve.

If you want to get your hands on some servos and controllers, drop by my demo stand at the Warley, NEC show next weekend. I'll have working examples of the Embedded Controls, MERG, Switch Pilot and G F Controls devices available to try out. I'll also have several working signals on display and be delighted to show you how they've been created, and do my best to help you with any signalling problems you might have. Stand number is E44. Steve.

Having the layout back home in its shed, I've been and retrieved a couple of the signals for my demo stand at the Warley, NEC show next weekend. Rob and I will be sharing stand E44. Please drop by for a chat and make yourself known. Steve.

For the record, here is the Luton van fully loaded and ready for the "Off". I've previously described how we use a Rotating Laser Level to ensure the accurate alignment of all the baseboards. Here's shot of it being used at Utrecht: Each leg and baseboard are labelled to ensure consistent use, and the bottom of each leg is marked with a "target" line. As each board is assembled, the leg adjusters are used to ensure the laser hits the target precisely. By so doing the layout is aligned within about a 1mm accuracy over its 15 metre length. Steve.

Here we go! Here we go! Here we go! Five of us spent this morning completing the dismantling of the layout and learning how it is packed for ttransport. We're off to Holland for the Eurospoor event in Utrecht on Wednesday. Every element of the railway has a particular bespoke place within the transport system, and some of us had to be taught about this so we'd be prepared for the assembly process when we get to the event. Typical trollies waiting outside the railway room: One loaded trolley, just a few more items before it will be ready to be covered for loading in the van: John explaining to Spike how the cables under the sector plate are stored for transport: Almost finished, covered trollies ready in sequence for loading. The large box between the first two trollies contains several buildings, and is carried on top of the first trolley, once loaded in the van. Its too tall to go through the roller door when it-situ. The padded containers stacked on the table each contain one unit of "pelmet" complete with flourescent tube, support leg, etc. I'll try to get a few shots of the loaded van before we set off on Wednesday morning for the overnight ferry to Rotterdam........ Steve.

Hi SJ, Your approach to the "twitching" problem seems to be giving benefits. Well done! With reference to the "gearing", I offer the following video of a typical application of a servo to drive a 4mm scale ground signal. Any gearing is limited to keeping the "horn" as short as possible. http://www.youtube.com/watch?v=LVqOpOYikoo As you will see, the movement required between end positions is quite small, but most controllers can cope with the accuracy required without any problems. With such a small movement, any "twitch" can be very noticable. Steve.

I managed a few pics during our operating session yesterday. Here's Rob, working on the new buffer stops on the Turntable roads. And close-ups of some of his work: Buffer stops Stone and Iron Work on the bridges One of the numerous roof pillars. Steve.

Hi Gordon, Thanks for your explanation, which I appreciate. As I said earlier in this topic, I have very little knowledge of Electronics, and I've proved it yet again. Steve.

Michael, Rob has been doing a lot of work on the weathering front. Each of the 60 odd pillars was the start, but he's now tackled several locos, the bridges you've noticed and he's on with the road way. I hope to get some more photos of his artistry tomorrow. Steve.

Les has every rignt to be happy as he contemplates his Masterpiece.... However, this shot shows how much more he still has to do! Les has started on the second "South" roof which will be similar in size to the first one. The "North" roof will then be similarly modelled in two main sections, but they are wider and taller! Steve.

Hi SJ, Yes, I've seen lots of "twitching" servos. The early MERG controller which I use on my demo. stand to run couple of Ground Signals, always pushes them up out of the ground on power up. The earlier Embedded Controls units were similar, but they did seem to twitch "within range", so not putting undue stress on the model. The final production of E.C. units didn't seem to twitch at all. The G F Controls units I've recently been involved with are designed to avoid the problem. Steve.

Hi SJ, I think the problem lies with the way the controller communicates with the servo. It supplies two main items: 1. The 5v power needed to run the motor. 2. The control signal - a square wave form of defined length, between 1msec and 2msec. The precise length between these limits defines the position to which the arm moves. The rate at which the wavelength is changed controls the speed of movement. I think the twitch is caused when the power is supplied to the servo before the control signal, causing the motor to try to move to some out of range location and at maximum speed. I believe the software in the controller should should ensure on startup that the control signal is sent before the power supply is turned on. Steve.

Les, If its at all possible, please bring them with you, even if you have to take them home again. Steve.

Les, That's fan-bloody-tastic! I can't wait to see it on Thursday? Steve.

This photo was posted on Page 1 of this topic, and shows clearly the close proximity of the pillars to the platform edge. Steve.

Dave, The pillars are now all fixed in place. What you are looking at is one of the (un-signalled) sidings. Steve.