BagEndJct Posted January 2, 2017 Share Posted January 2, 2017 I am just resurrecting my old layout and installing Elink and Railmaster. I have a couple of Hornby Decoders and point motors. I have found I have an old Hornby Dublo Travelling Post Office (TPO) which is in pretty good nick. It is operated by a push button taking 12v from the accessory supply I guess. Can this be operated by connecting it to a Decoder, I wonder? I had one of these on my original Dublo layout and it really was the highlight of my setup! Link to comment Share on other sites More sharing options...
96RAF Posted January 2, 2017 Share Posted January 2, 2017 I suppose it all depends if your TPO will be running on normal track and if the 12V bit you are talking about is off-track electrically, in which case yes you could operate it using a decoder, but only if you can find one that will switch the 12V load, and whether it will operate from the decoder motor connection or need to have the function putputs ganged together to carry the load. Does it have a label anywhere saying what volts and amps it needs. Link to comment Share on other sites More sharing options...
Fishmanoz Posted January 2, 2017 Share Posted January 2, 2017 A little more info is needed on the 12V supply required to give a definitive answer. Is it DC or AC and how much current is needed. Given it is DC and within the current capability of say an 8247 accessory decoder, then it could be operated directly via the 8247. If AC and/or higher current, then the 8247 could still be used to control it, but via a relay. Link to comment Share on other sites More sharing options...
BagEndJct Posted January 2, 2017 Author Share Posted January 2, 2017 OK, thank you. I have the box and instruction leaflet and will dig it out and post any info from there. Link to comment Share on other sites More sharing options...
BagEndJct Posted January 3, 2017 Author Share Posted January 3, 2017 As ever, I really should have read the instruction leaflet (and box) thoroughly before posting on here! On the box it states it's the "two rail version". I looks like plastic or nylon wheels have been fitted to avoid shorts which would not have been a problem on Dublo 3-rail system, I guess. It clearly states that the supply can be 12-15v ac or dc. The power goes to a pick up rail on the lineside equipment. A pickup on the coach gets its power from that when the button is pressed. So I shall give it a test, setting it up as an uncoupler. As I recall, I can set the duration of the power to whatever it needs. For those interested, I'll report back. Can't wait to get this working. Link to comment Share on other sites More sharing options...
Fishmanoz Posted January 3, 2017 Share Posted January 3, 2017 Yes, you can certainly set the pulse duration all the way to continuous, the issue still though is how much current the system needs and whether the 8247 can supply it. Link to comment Share on other sites More sharing options...
96RAF Posted January 4, 2017 Share Posted January 4, 2017 It would be handy if the R8247 could fire more than one port simultaneously then you could strap several together to feed the load, when we find out what it is. I have no idea how this TPO thing works but a push button to me suggests a solenoid to flip the bag catcher out, so continuous output may not be the way ahead. We (I) need to find out more about how it works from the Hornby Dublo elder statesmen/women on here. Link to comment Share on other sites More sharing options...
LCDR Posted January 4, 2017 Share Posted January 4, 2017 The Hornby Dublo TPO is operated by a solenoid in the coach. There is a metal shoe sticking out of one side of the coach in the centre underneath. The electric current is supplied via a raised rail attached to the base of the pick up / set down base unit apparatus parallel to the track. A shoe on the coach contacts the rail as the coach passes. If a push button is depressed as the coach passes it energises the extra rail and the mechanism operates, but if not the coach just passes by. The current returns through the body of the coach to the wheels, and then to the rail which is attached to a screwed terminal on the base. The wheels are plastic on one side and steel on the other. The base unit is wired to the power unit through a push button switch. It was origiinally made as a three rail accessory and this is most commonly found nowadays. The track was permanently incorporated into the base unit matching a standard straight rail. When Hornby Dublo went 2 rail a new base unit was made replacing the tinplate with plastic. These are fairly rare. I have seen the 3 rail ones but the following is the only sight I have had of the two rail version./media/tinymce_upload/7d3ee44b1ae1d30ac49578dd2db39230.jpg Link to comment Share on other sites More sharing options...
Chrissaf Posted January 4, 2017 Share Posted January 4, 2017 Having seen LC's description of operation, I think to be on the safe side (see comment below), I would use relay contacts to replicate the mechanical switch function. Then fire the relay via DCC using a R8247 port or equivalent. Using the pulse output option set to a longish pulse time. If you use the continuous output, then you would have to keep remembering to reset it again after each use.."Without the relay contacts acting as an isolator, you would be connecting the output of the accessory decoder directly to track voltage, not a good idea." Link to comment Share on other sites More sharing options...
96RAF Posted January 4, 2017 Share Posted January 4, 2017 I would make that relay circuit to replicate the old logic whereby when the button is pressed the relay is held in and when released the relay opens. Therefore the R8247 channel output time-on would have to be be best guessed based on the TPO time over track at the bag-drop area, noting that the time-on CV (515-518 depending upon which output channel is being timed) can be adjusted up to a maximum of value 255 i.e. 25.5 seconds. Here is a circuit showing how to fire DCC from R8247 into a relay coil - in this case to fire a solenoid motor each way, but equally the relay contacts can fire your TPO functionality and/or make a signal respond (showing TPO ready?). /media/tinymce_upload/06c8829a3fbd98b7a5488001b6e05e29.PNG Link to comment Share on other sites More sharing options...
Chrissaf Posted January 4, 2017 Share Posted January 4, 2017 A slightly simpler circuit diagram../media/tinymce_upload/e78fece24928865fa97f014b01a48de5.jpg. Link to comment Share on other sites More sharing options...
BagEndJct Posted January 6, 2017 Author Share Posted January 6, 2017 I'm grateful for the thoughts about how this can be operated from the electrical point of view but, having looked again, there are physical problems which I think will prevent me from getting this working. To start with the coupliings are not compatible with modern ones and there does not seem to be a way of changing them. The design of modern track is different from the track this was designed to fit along side of and some serious surgery would be required for this to fit. The model I have is indeed the 2-rail version based on the Dublo 3-rail version I had all those years ago. And, yes there are plastic wheels on one side and metal the other. I assume the modern GWR "Night Mail" would not operate nearly as satisfactorily as this Dublo beast used to. The thrill of one metal bag being picked up from the hook while another bag was thrown out, at speed, was something special for this, at the time, 12year old! Link to comment Share on other sites More sharing options...
NIMBY001 Posted December 5, 2018 Share Posted December 5, 2018 There is good video on youtube showing how to prepare existing track for the line side apparatus.Title - Dublo TPOLink - See Video On Youtube Link to comment Share on other sites More sharing options...
Yelrow Posted December 5, 2018 Share Posted December 5, 2018 I have both the Hornby Dublo, 3 rail, ( which i have running, and the 2 rail plastic version, which is an absolute pain . Basically, as the plastic operating bits are only designed to fit into hornby normal track. Trying to set it up with flexi, is enough to throw it out the window. There is a separate thread on here about these sets, which has frustrated many. As an aside, the Dublo one, needs the lead mail bags, as plastic ones are way too light and end up anywhere, apart from in the receptical. Link to comment Share on other sites More sharing options...
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