Linking shuttle lines and multiple options for a shuttle

[beavercreek]

Hi David
Thanks for the input.
I have used LGB and Aristo shuttle units but they did not have enough power handling for the inclines and size/make of locos that I used. So I bought two 8amp ones from ebay guy who makes them. So far they have been great. I think that they detect and time if that makes sense. The sensing tells the unit to reverse polarity while the timer gives the pause period at each end.

 

[Richie]

Hi Mike
Sorry can't help you on electrics Good luck hope it all works out for you should look great once it's done with the new links

 

[Cliff George]

I suspect there is no sensing involved, although I couldn't find any explicit instructions.

I found this on ebay in completed listings:

http://www.ebay.co.uk/itm/LGB-8-Amp...=UK_Trains_Railway_Models&hash=item4aad292a73

I would imagine that when the timer expires the unit just reverses the polarity and keeps going until the timer expires again and then it reverses the polarity again. The train stops at the end because of the diode protected section. I imagine that one has to adjust the timer and throttle setting so that the loco gets to the end of the shuttle line before the timer expires (otherwise it will just do an immediate reverse with no stop wherever the train is). Possibly this means that the timer will need adjusting when alternate shuttle end points are used (or just use the max time and accept some end waits will be longer than others).

I agree that the SPST switches are not required.

 

[Gizzy]

What I am not sure about whether the diodes that are not being employed for a route would cause the shuttle unit to sense that a train has not 'passed through' a diode when it has 'passed through on another one on the line.....
for example:
the diodes that are in the two spurs (diode 4 and diode 5), would they interfere with each other when a train, let's say 'passes through' diode 4, comes to a stop...would the shuttle just see the diode 4 activity and consequently reverse the polarity and after a wait make the train reverse out etc

The diode only switches the spur it is fitted to, so a diode in Spur 5 will not affect any other diode in any other spur.

Sorry if this is teaching granny to suck eggs, but someone may find this useful!

The diode just works as an 'ON' switch on the rail it is attached to when your controller or in this case, shuttle polarity is say positive, but as an 'OFF' switch, when the controller/shuttle is of the opposite polarity, and cannot switch or interact with a diode in another spur....

If the bottom rail is a positive voltage with respect to the top rail in the diagram above, current will flow through the diode in the direction of the arrow, to the rail close to the buffer, through the loco motor and into the top rail. The loco will move away from the buffer. (Should it move towards the buffer, turn the diode round so the arrow points the other way.)

If the top rail is positive, the lower section of rail next to the buffer stop has no return, as the current flow would be in the wrong direction, against the arrow of the diode. The loco cannot move, or crash into the buffer as the rail is switched off.

 

[beavercreek]

Well, may I take this chance to thank you who have contributed to this thread.
Thanks especially to Gizzy, Tony, Cliff and to Neil (by pm) who have been very patient and helped me to either confirm that I was right in parts or needed assurance and advice in others.
I now know that the diodes in other spurs will not affect a diode that has been 'opened' by a loco and therefore not affect the shuttle unit.
If I have only one loco linking across the two shuttle lines then I can get rid of all of the SPST switches as for example the quarry shuttle can control a loco either in the quarry circuit or all the way to Arrowhead and back.
The shuttle unit that normally controls the 'local' train can also control a single train to the Pointrock sawmill.
BUT if i have two trains somewhere on the local with one supposed to be waiting while the other does its thing, Neil has pointed out in his pm, there does have to be a way to isolate one or other of the trains while the shuttles are working on them. For example if both trains are at diode 4 and 5, obviously both will want to move out when the shuttle unit controlling the line times the reverse and supply.
So in my plan, either when the quarry train has done its stuff, it will need to be isolated by the DPDT ( or automatic isolation system) when it gets back to the quarry section or is at the other end (let's say diode 4) so that the shuttle unit then only controls the 'logging train' or the 'local'.
OR the logging / local train have to be isolated somewhere eg at diode 4 or 5 or at diode 6 so that they do not start moving when the quarry train is being controlled by the shuttle and is on the 'loca'l line.

The new amended plan: