gormo Posted June 11, 2013 Share Posted June 11, 2013 G`day Folks, I am interested in building some block instruments and I wish to use the needle pointer system as was the norm in the old instruments. I have sufficient information regarding systems that use colour lights and rotary switches, however I would rather try and use a needle pointer instead. Can anyone suggest a suitable method of operating a pointer...eg. solenoids, levers, or whatever. I know Triang used to have a system many years ago, but I am not aware of how it worked. Thanks in anticipation Gormo Link to post Share on other sites More sharing options...
micknich2003 Posted June 12, 2013 Share Posted June 12, 2013 Use a voltmeter with a centre zero position. Look up the last few issuies of "Model Railway Journal", for those inclined to have instruments etc, a good series of articles. Certainly not my scene. Link to post Share on other sites More sharing options...
LNERGE Posted June 12, 2013 Share Posted June 12, 2013 I did make an indicator once using two post office relay coils to attract an iron flag on the spindle behind the indicator face. It was a bit big and cumbersome. Diodes selected which coil was energised. No photo's i'm afraid. Link to post Share on other sites More sharing options...
RMweb Premium martin_wynne Posted June 12, 2013 RMweb Premium Share Posted June 12, 2013 Can anyone suggest a suitable method of operating a pointer...eg. solenoids, levers, or whatever. A centre-zero panel meter works, but doesn't look very traditional. I suggest using a servo to operate a proper pointer: Maplin do a kit: http://www.maplin.co.uk/servo-and-controller-board-kit-528801 Link to post Share on other sites More sharing options...
RailWest Posted June 12, 2013 Share Posted June 12, 2013 A few points here:- 1. Do you just want a generic block instrument, or to replicate that of a specific railway to match your model? Not every type used pointers. 2. Pointers were worked by 'induced needle' electro-magnetic coils. If the current failed, the pointer reverted to its 'normal' position by gravity. I'm not sure that you could replicate that by servos. 3. Do you want a small instrument to mount into a panel, or would you be happy with something larger on a shelf? 2nd-hand block instruments are expensive on the railwayana market, but you could find something like a basic BR bakelite signal repeater quite cheap for a battered item, which could be adapted. Just make sure that the pointer swings freely - the needle pivots often broke. Link to post Share on other sites More sharing options...
Jon Fitness Posted June 12, 2013 Share Posted June 12, 2013 Or try using one of these. A servo tester. Plug the servo in one end, power at the other end, turn the knob and the servo moves in response. JF Link to post Share on other sites More sharing options...
gormo Posted June 12, 2013 Author Share Posted June 12, 2013 G`day Folks, First of all thank you all for the responses,..........I guess what I am aiming for more specifically is a generic form of instrument. I would think at this stage, from what I have learned from your responses, I would probably elect to go with the centre zero volt meter, panel mounted with an appropriate overlay on the face. The meter would be used in conjunction with a three position rotating switch and single strike bells.........I`ve already sorted the bell problem. Again .......thank you all........ and any other input is welcome. Cheers Gormo Link to post Share on other sites More sharing options...
LNERGE Posted June 12, 2013 Share Posted June 12, 2013 2. Pointers were worked by 'induced needle' electro-magnetic coils. If the current failed, the pointer reverted to its 'normal' position by gravity. I'm not sure that you could replicate that by servos. 3. Do you want a small instrument to mount into a panel, or would you be happy with something larger on a shelf? 2nd-hand block instruments are expensive on the railwayana market, but you could find something like a basic BR bakelite signal repeater quite cheap for a battered item, which could be adapted. Just make sure that the pointer swings freely - the needle pivots often broke. The servo 'stay put' feature could be useful if trying to replicate something like a GE Tyers one wire two position block. Cheap blocks do turn up from time to time. Likewise with signal repeaters. What's wrong with using lights? It's common enough on the big railway... Edit to add... Link to post Share on other sites More sharing options...
peach james Posted June 12, 2013 Share Posted June 12, 2013 I'm using Tam Valley Servo drivers http://www.tamvalleydepot.com/products/dual3way.html to drive the arm back and forth. There are a few photos of the setup on my flickr account: http://www.flickr.com/photos/47105471@N05/sets/72157629408307454/ James Link to post Share on other sites More sharing options...
gormo Posted June 13, 2013 Author Share Posted June 13, 2013 G`day Folks, Once again........thanks for the contributions.........they have made me aware of various options and clarified things. Today I have made some electromagnets and a needle pointer and at the end of the day I have a combination that works. So I will be building my block instruments as a complete scratch build and hopefully they will look like little replicas of the real thing. Mean time..........back to the railway Cheers Gormo Link to post Share on other sites More sharing options...
SimonME46 Posted June 30, 2013 Share Posted June 30, 2013 I'm looking into this too, so thought I'd continue to ask questions on this thread too, if that is Ok Gormo? May I ask what your bell solution is? I've gone with 30V DC Voltmeter as I have a bi-polar 12v dc power supply running, so can use 0v, 12v and 24v as the positions, and just adjust the overlay/make a cover for the needle Also wondering whether the block instruments for a terminus always had both indicators for both up and down lines, or would the departing line only have an indicator for the block in advance? Link to post Share on other sites More sharing options...
RMweb Gold beast66606 Posted June 30, 2013 RMweb Gold Share Posted June 30, 2013 Also wondering whether the block instruments for a terminus always had both indicators for both up and down lines, or would the departing line only have an indicator for the block in advance? (UK) Terminals have one block for each pair of lines, so a double track terminus would have one block. (Additional running lines to the next box may mean more blocks of course) Link to post Share on other sites More sharing options...
gormo Posted June 30, 2013 Author Share Posted June 30, 2013 I'm looking into this too, so thought I'd continue to ask questions on this thread too, if that is Ok Gormo? May I ask what your bell solution is? I've gone with 30V DC Voltmeter as I have a bi-polar 12v dc power supply running, so can use 0v, 12v and 24v as the positions, and just adjust the overlay/make a cover for the needle Also wondering whether the block instruments for a terminus always had both indicators for both up and down lines, or would the departing line only have an indicator for the block in advance? Hi Simon, No worries..........ask as many questions as you like. My Bell solution is a bell as used on a reception counter in a hotel or motel. You hit a little plunger on top of the bell which in turn rings the bell. The bell is struck inside by a hammer which in effect is a pendulum suspended from the inner top part of the bell assembly. The downward push of the plunger forces the pendulum to one side of the inner bell and strikes it. When the pendulum returns to center position it pushes the plunger back up...........very simple. What I propose to do is fit a standard solenoid point motor just below the base of the bell so that the vertical pin, which would normally pass through the tie bar of a point, makes contact with the lower part of one side of the pendulum. When you apply a burst of volts to the solenoid ( one way only ) it propels the pendulum to the inner side of the bell. The point motor also needs to be fitted with an appropriate light weight return spring. Obviously, the plunger now becomes redundant and can be quite easily removed. I don`t have any pics at the moment, but a mock up I built works. In Sydney we have a Japanese retailer called " Daiso".......every item in the store is $ 2.80. They had the bells and I bought four ........I am not sure if that company has a store in Canberra???? The system I am trialing for the indicator is a short length of 0.90mm wire which passes through a timber fascia and connects to a modified hand from an analogue quartz clock ($3.00 @ Big W). This is the indicator needle. At the back of the fascia the wire is bent at 90 degrees and hangs down like a pendulum between two electromagnets. The magnets are powered by a 6 volt lantern battery. The magnets are home made based on research from the internet.You apply power to one magnet at a time which drags the indicator needle to either " Train On Line " or " Line Clear ". With no power ,the needle returns to center, which is " Line Blocked ". I have a mock up in the shed and it works very well. Fascia panel artwork has been created in the Open Office drawing program. I hope this has been helpful ..............if I may be of further assistance........don`t hesitate to ask. Cheers Gormo Link to post Share on other sites More sharing options...
RailWest Posted June 30, 2013 Share Posted June 30, 2013 Posted Today, 07:39 SimonME46, on 30 Jun 2013 - 05:13, said: Also wondering whether the block instruments for a terminus always had both indicators for both up and down lines, or would the departing line only have an indicator for the block in advance? >>>(UK) Terminals have one block for each pair of lines, so a double track terminus would have one block. (Additional running lines to the next box may mean more blocks of course) I would suggest that the answer is not quite as clear-cut as that. In essence, your 'typical' block instrument will consist of two parts - one for accepting trains coming towards you on one line, the other to indicate the situation for trains going away from you on the other line. Clearly a terminus at the end of a double-track line would need both parts. Whether both parts were in one instrument case or two separate cases depended upon the type of instruments being used. Whilst there would always be some form of indicator for trains "going away from you" (otherwise you would have no indication whether the chap at the next block post had accepted your 'offer' or not), that was not always the case for "trains coming towards you". For example, with the Preece instruments beloved by the L&SWR you had the operating switch handle only for the latter and it was the position of the handle which told you what the situation was. Having said that, for what you appear to be modelling then I would suggest that two indicators would be appropriate. Link to post Share on other sites More sharing options...
gormo Posted June 30, 2013 Author Share Posted June 30, 2013 G`day Folks, I have attached a PDF with some samples of labels I have been working on for my block instruments. They were created in the free office suite "Open Office" using the drawing program. Sample Block Instrument Labels.pdf Cheers Gormo Link to post Share on other sites More sharing options...
SimonME46 Posted June 30, 2013 Share Posted June 30, 2013 Excellent replies, very helpful. The bell solution makes perfect sense... Link to post Share on other sites More sharing options...
RailWest Posted June 30, 2013 Share Posted June 30, 2013 Very nice, but.... If you are going to have the needle point downwards, with the legends below the needle, then the same should apply to the legends for the commutator/switch. This convention ensures that you rotate the commutator in the same direction as the needle moves - clockwise or anticlockwise. If you compare (say) WR and SR instruments, you will find that the former have Line Clear on the left, the latter have it on the right. This is because the former have the labels below the needle, the latter has them above the needle. The commutator was always rotated in a clockwise direction to give LC. Having said that, I believe that you will find examples of the BR black-and-white 'plastic' blocks with LC on the left or LC on the right, sometimes in the same instrument! This is because they were made to match the convention of whatever it was that they were replacing. Link to post Share on other sites More sharing options...
LNERGE Posted June 30, 2013 Share Posted June 30, 2013 Link to post Share on other sites More sharing options...
micknich2003 Posted June 30, 2013 Share Posted June 30, 2013 Block face.jpg Richard, your block dial brought back a few memories, now well over 21 years since I last "Pegged Up", or for that matter pulled a lever. Mick. Link to post Share on other sites More sharing options...
gormo Posted June 30, 2013 Author Share Posted June 30, 2013 G`day Folks, The position of the labels depends on really which church you follow. I looked at lots of images of block instruments on the net and there are many variations. I think once you adapt to any particular system.......that becomes the norm in most cases. I rather like the look of the first instrument. Here are some examples below which show the direction I will follow. CORRECTION !!........if you wish to see different types of block instruments you should do a search on google entitled " Block Instruments "........... Cheers Gormo Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted June 30, 2013 RMweb Gold Share Posted June 30, 2013 Don't follow the bottom one! It's an instrument for Tokenless Block (on single lines) Link to post Share on other sites More sharing options...
RailWest Posted July 1, 2013 Share Posted July 1, 2013 >>>Don't follow the bottom one! It's an instrument for Tokenless Block (on single lines) ..... AND it is one of my pictures too Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted July 1, 2013 RMweb Gold Share Posted July 1, 2013 >>>Don't follow the bottom one! It's an instrument for Tokenless Block (on single lines) ..... AND it is one of my pictures too I wonder where the norty button is? I ticked like because I don't hold with unauthorised theft of other folk's stuff off the 'net but regrettably is a problem we have to live with. Link to post Share on other sites More sharing options...
gormo Posted July 1, 2013 Author Share Posted July 1, 2013 Ok........sorry about that.........I`ll sort that out. Cheers Gormo Link to post Share on other sites More sharing options...
RailWest Posted July 1, 2013 Share Posted July 1, 2013 Don't worry too much - given the nature of its re-use and the fact that it was not used for commercial purposes, I'll let you off this time I've had far worse plagiarism..... On a general point though, unless one actually owns the copyright of a picture, or has the permission of the copyright owner to display it, or it is simply out of copyright anyway, then it is best simply to post a link to the source of the picture - avoids any possible problem then, and we can still get to see the picture anyway. Link to post Share on other sites More sharing options...
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