Automatic Reversing Unit.

KeithT

KeithT

Hillwalking, chickens and - err - garden railways.
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Many moons ago, 5yrs to be precise, I fiddled unsuccessfully with a Crest reversing unit to no avail.
HWMBO has now commented that she would like to see the rack operating independently with a train on it at all times. :-0
It is time I bit the bullet and got the LGB reversing unit but do they still do them and if so is the current unit as good/reliable as the original ones?
I can run analogue, MTS 2 or MTS 3. Two of my rack locos are analogue and one is factory chipped. Does the operating system make any difference. I asked similar questions last time but they related to the Crest unit.
 
The LGB reversing unit can be found on Ebay sometimes. It only has a ceiling of 1 amp and will not work above that.
Before I changed from DC analogue to DCC on my shuttle line, I used an 8 amp DC analogue shuttle unit. This would cope with any loco and load.

I changed to DCC shuttling using a Tam Valley shuttle unit with a Tam Valley DCC booster (small extra board) to bring it up to 5 amp handling. It does not need a central station and is self powered and will automatically 'shuttle' any loco with a DCC address between 1 and 99 (it can handle 4 digit addresses with a cheap add on).

I do still have a brand new unused 'Bazooka' DC analogue 5 amp shuttle unit that I would be happy to pass on.
I got the 8 amp one and did not need the Bazooka jobbie.

If you are interested just pm me (or 'conversation' me)
 
The current LGB unit, product number 10345, was introduced last year, has a 3A rating and is quite pricey.
LGB and Massoth chips, and probably several more brands, can be programmed to enable a loco to slow gently, pause for a fair while and then gently reverse in the opposite direction when running on DC.
A trigger near each end is needed to activate a relay that reverses the track feed wires.
 
Triggers to reverse the track feed for the analogue unit (that's how I was planning on doing mine) but how does the digital work? Sounds interesting if it can accelerate and decelerate rather than 'instant stop/start
 
Frank Gallagher said:
Triggers to reverse the track feed for the analogue unit (that's how I was planning on doing mine) but how does the digital work? Sounds interesting if it can accelerate and decelerate rather than 'instant stop/start
Click to expand...

Analogue shuttle units work by having a timer which reverses polarity after a set time.
The diodes that are in a gap at each end of the track (on one rail) only let the power go one way.
When a loco crosses at one end it stops (due to the one way diode) until the the shuttle unit reverses polarity.
Then the loco (being DC 'reverses' back until it crosses the other diode gap and it stops again waiting for the next timed reversal of polarity to go 'forward'.
The timer time includes the time for the loco to go from one end to another so it has to be set for total journey time between the gaps.

On the Massoth Dimax system, DCC shuttles can be done by using a feedback module which has magnetic sensors in the track (at either end or also in the middle) and the module needs to be programmed to do what it needs to.

The Tam Valley DCC shuttle unit works totally independently from a powered central station unit.
The loco decoder will have the 'soft' start and stop already programmed into the decoder for 'normal' use so this will still happen on the shuttle.
The TV shuttle also has timers which set the journey/wait time (or a pause in the middle somewhere with another 'triggering' gap).
The rail gaps, one at each end (and the option of one in the middle) are on the same rail (like the DC ones) but do not use diodes.
The loco will stop (with the already programmed deceleration) and wait for the unit timer to tell the DCC signal to command it to reverse back (again with the 'soft' accelerated start) till it crosses the other gap where a second timer will give the DCC command for it to go back again etc etc.
The two timers (in fact there are three - one for the middle stop) can be set independently for long or short stops etc.
The unit also has a speed control so that the loco speed can be altered (of course you could not use your system handset as the TV shuttle is an independent system)

DCC locos can be used on a DC shuttle (but be careful of on board 'keep alive' capacitors)
DC locos cannot be used on a Tam Valley DCC shuttle
 
Has anyone been brave enough to leave a LGB buffer-stop shuttle out in the garden for any length of time?
 
Cheers Mike I'll look at that TV jobbie, I was staying analogue as I thought the wiring would be simpler as mainline is DCC
 
Frank Gallagher said:
but how does the digital work? Sounds interesting if it can accelerate and decelerate rather than 'instant stop/start
Click to expand...

With a Massoth or LGB chip the relevant CVs are CV 3 for acceleration rate, CV 4 for braking rate and CV 58 for delay time.
Apply a steady DC voltage to the track to suit the maximum speed required. When this is instantaneously reversed a chipped loco will slow down, pause and then accelerate in the opposite direction. It doesn't work if you turn a DC controller down and then up again in the reverse direction as the change has to be rapid.
When I set this system up I install track diodes at each end on the buffer sides of the reversing relay triggers. When the relay triggers the track beyond the diode is live, but if the relay fails to trigger for any reason the polarity doesn't change so the last bit of track is dead preventing the train hitting the buffers.
 
Can't say anything about DCC I am afraid, but I have lots of experience using LGB, Playmobil and custom made analogue shuttle units, the latter have been in the garden now for around four years.

I keep mine in plastic tubs in my garden. These keep the water out but allows the units to breathe. The 'Really Useful Boxes' are perfect as the wires can also go out through the 'breathe' space. Cold, heat, rain etc have never been an issue.

That Massoth unit and many others rely on the train running over the diode to stop drawing power before the timer kicks in. That means that the run can be of any length you like without worrying about the train taking too long.

A chum made me some great units based on this principle. One shuttle line crosses the main line and sometimes the shuttle train has to wait at the signal controlling the junction. This would normally activate the timer, but I have rigged up 'holding load' in the form of a simple bulb that the shuttle train activates before it reaches the crossing and switches it off after it has passed! That means that the shuttle train can wait as long as necessary at the crossing without the timer kicking in!

The only downside to any of these units is that you must never run anything else that picks up from the track, except the loco course!

The Playmobil ones were widely available at one time and still turn up on e-bay. Sometimes quite cheaply. They are not as good as the LGB ones, or I imagine the Massoth unit. For example they lack dwell adjustment, but were widely used in shop window displays throughout the track powered Playmobil era, so they are quite robust. I have never used those outside except on temporary layouts.

James
 
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Frank Gallagher said:
Cheers Mike I'll look at that TV jobbie, I was staying analogue as I thought the wiring would be simpler as mainline is DCC
Click to expand...

Hi Frank. The wiring for the TV DCC shuttle is nearly as simple as the DC units but if your locos need more than 1.5 amps you will need the additional DCC booster.
It is a small board and is easily hooked into the shuttle unit.
Here are the wiring diagrams for the Tam Valley shuttle unit without and with the intermediate 'station stop'.

TV shuttle.jpeg

tv shuutle with station stop.jpeg


shuttle unit.jpeg
 
PhilP said:
Has anyone been brave enough to leave a LGB buffer-stop shuttle out in the garden for any length of time?
Click to expand...

Hi Phil
I used an LGB shuttle unit (the one in the buffer) when I first built the quarry shuttle line about ten years ago. I kept if outside all year round for about 3 years but swapped it out when the power handling (1 amp) became too limiting.
The new versions (LGB and Massoth) handle up to 3.5 amps but as far as keeping them outside..I think that stuffing them in a buffer or similar may not cut it!
 
Neil Robinson said:
With a Massoth or LGB chip the relevant CVs are CV 3 for acceleration rate, CV 4 for braking rate and CV 58 for delay time.
Apply a steady DC voltage to the track to suit the maximum speed required. When this is instantaneously reversed a chipped loco will slow down, pause and then accelerate in the opposite direction. It doesn't work if you turn a DC controller down and then up again in the reverse direction as the change has to be rapid.
When I set this system up I install track diodes at each end on the buffer sides of the reversing relay triggers. When the relay triggers the track beyond the diode is live, but if the relay fails to trigger for any reason the polarity doesn't change so the last bit of track is dead preventing the train hitting the buffers.
Click to expand...

Hmmmm interesting

Just to add, I believe the Massoth unit is a direct replacement and fits into the LGB wooden bufferstop
 
  1. Many thanks for the wealth of info'.
  2. I hope I am not reading this wrong but it does appear that mixing analogue with DCC locos on the same track, not at the same time, is a no go. Am I correct?
  3. The locos BTW are 2 analogue Ballenbergs and the little DCC FO box electric.
  4. (I have no idea why numbers have appeared on the left of the post.) :-0
 
Has anyone had any experience with "Block Signalling" train shuttles ?
 
Hello Mardy,

I am trying to work out what that might be? Can you enlighten me?

James
 
Thanks Mardy,

That explains a gret deal. I was imagining flights of trains shuttling up and down magically avoiding collision with each other!

So as you may well already have guessed, the anwer from me is No experience at all! Sorry!

James
 
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