Northern Tablelands Express approaching Ardglen Tunnel

Northern Tablelands Express approaching Ardglen Tunnel
Click on the above photo to see the Main North Album at Flickr

Thursday, September 25, 2014

Uncoupling at Ardglen automatically.


March 2015 - Update. What I am doing when uncoupling the Banker at Ardglen,

On the Banker loco the front Kadee Coupler's Claw is permanently locked open using Blu Tack (modify for a more permanent fix later), preventing the Banker from coupling up to the Guards Van. The only issue with this method, the driver of the Banker must be very vigilant and to not allow the Banker to "separate" from the Guards Van - not very prototypical but this method allows simple and easy uncoupling anywhere at Ardglen. 
NOTE: I have tried pushing the Banker against the Buffers of the Guards Van but due to small (24 inch) radius of my curves, the Buffers, LOCK and this is too dangerous on the Main North, Ardglen is 1,500 mm above the cement floor.  

Adding ballast to the track is the final major chore to finishing a "scene" so I better mount some Uncouplers at Gosford, necessary for the "change of loco" for trains going to/from Sydney, at Ardglen to "disconnect" the "rear end" Banker and other places.

I am experimenting with the Kadee 321 Permanent Magnet "ramps" and Electromagnetic Uncouplers from a Dec 91 AMRM article, similar to the Kadee 307.
I have temporarily fitted the Kadee 321s to one of the Exchange Sidings at my Sulphide Smelter Works and using "Delayed Action" uncoupling to shunt the 16 wagons into their appropriate Siding. I have also fitted these 321s to Gosford Yard for the "change of engine" procedure. Many of you would have already experienced, these 321 magnet cause unwanted uncouplings when going slow over them. Their ease of operation with no buttons to be pressed and held, while using the Throttle to "reverse/slow" the loco/train, their ease of installation and cheapness, sort of offsets the unwanted uncouplings. Well maybe, time will tell.

I need to "uncouple" the Banker at Ardglen, that's 1700 mm off the concrete floor. How would I do this:
  1. Fit a cover over the Front Coupler or something along these lines.
  2. Remove the Claw part of the Front Kadee so as it could not couple - sounded good.
  3. Don't have a Front Coupler on the Banker and use the Buffers on both the loco and Van - sounds good but buffer lock is possible and maybe damage with the loco/Van making a trip to the floor.
  4. Fit a Kadee 321 magnet but there are "unwanted uncouplings".
  5. Fit an Electromagnet Uncoupler. 
I decided on using one of my Bob Olde Electromagnet units. Now to operate it.

Just press a button at the appropriate time while slowing the train/loco with your Throttle. Well you know me I've got to add some DCC/electrics here. As I don't want any DCC input to the Uncoupler, it'll just be electrics this time.

Electromagnet units draw a couple of Amps and need DC or AC. So I needed to install a Button, Relay and Power Supply. Mark I version was okay with just the button/relay and 20 Volt DC Power Supply, but "needed" to "automate" it. I'll spend days on hobby electronics stuff but won't fit Accessory decoders and Point Motors to Points. That's another story.

I made a 15 second Timer to energise the Relay so I did not have to hold down the button and I installed an "In Track" Sensor firstly a Reed Switch and a Magnet under the Banker's Tender. but other locos energised the Uncoupler when their speaker's magnet, energised the Reed Switch. Mark III was born with using IR LED and Sensor operating another home made circuit based on a LM339 Comparator chip. Eureka no more phantom uncouplings. Note: I use Rob Paisley's :Electronics for Model Railways" site, at:
                          http://home.cogeco.ca/~rpaisley4/CircuitIndex.html

Now for a bigger problem that I did not initially see but I have had problems with circuits using 555 Timer ICs, in the past, the Timer circuit would energise the relay/Uncoupler whenever a Fluorescent Light was turned on or off and when initially powering the Power Supply. Two days later and continual modifications to the "my" circuit built on Veroboard, shown below, it works.


My Murrurundi Bankers will be only located at Murrurundi Loco and they'll be my two DJH 50 Class locos but for the time being while testing I'm using an Austarins C36 as it was easy to add the IR LED into the Tender's floor and connect it to the decoder's internal 12.0 Volts DC via a 1 k resistor. So whenever this loco is powered, the IR LED is shinning it's IR light on the centre of the tracks. I hope it does not discolour my ballast.

All that's necessary for the Operators is to do, is:
  1. The FRONT loco operator slows down his loco as the Van approaches the "Tree" (see video), to take the tension out of the couplers that introduces coupler SLACK that's necessary for uncoupling, With the middle of the Van behind the Tree, the fascia LED is illuminated indicating the Uncoupler has energised (15 seconds).
  2. The REAR operator slows loco to a STOP when the Van/Loco Couplers, lines up with the Tree.
NOTE: The above procedure would be more difficult with medium to high values of Momentum in the Banker loco.

With the "On the Fly" uncoupling done, the operator of the Banker would either return back to Murrurundi (most cases) or run around the train and proceed to Werris Creek "in front of" the train or double head with the train loco, depending on Banker engine requirements. As there is only 15 feet from Ardglen to Werris Creek as compared to the 60 feet from Murrurundi to Ardglen, rear end "banking" will be only done on DOWN trains from Murrurundi to Ardglen.

While this Electromagnet type of Uncoupler  is what's fitted to Ardglen and provides near to 100% operation, I am still choosing which type to install at Gosford and other locations. The Electromagnetic types have the front running but the ease of installations of the magnets are gaining momentum but depending on how many of the "unwanted uncouplings" happen in my experimental locations over the next few months, will determine the final outcome.

The video shows banking up to the Ardglen Tunnel and then automatically un-coupling at Ardglen.