Friday, June 29, 2012

A warning - Please read

While reading the Aus_Model_Rail Yahoo Group tonight I noted a discussion on the use of DCC high amp boosters (10amp), short circuits and the way to handle them with circuit breakers, etc. The discussion has prompted this post and I pass on a warning for those using PCB sleepers with copper on both sides.
Recently I was at the first running night on a friend's new layout, now this layout had handbuilt points using the Fast Tracks method. My friend had been having mysterious short circuits that very day and said that the layout was out of action due to the short. On turning the system on so that we could check for the short he found that it was now working so the running night proceeded.
All was good for a while then as I was shunting his branchline terminus I saw a small approximately 8mm ball of flame erupt from one of the sleepers on a point. I quickly called for the layout to be turned off as the cause was immediately apparent.
There was a short caused by the track pins/spikes passing through the sleeper which had the usual piece of copper removed between the rails, however the copper layer on the bottom was still there and both pins/spikes were touching the copper at the top and the bottom of the sleeper hence a short circuit.
The scary thing here is that this is relatively standard practice in point building and as we often leave the power on the layout when we leave the room a fire could result.
The solution is simple, do not put a track pin on both ends of a PCB sleeper if it is double sided.
I checked my handbuilt points and sure enough I have the same situation on my Cassilis branch terminus but luckily mine aren't shorting.
I am going to remove one track pin/spike from one side of each PCB sleeper.
The interesting thing with this situation is that the booster didn't trip it just kept putting out the amps. I should also point out that the DCC booster was only rated at 5 amps, a very normal booster.
So beware, you have been warned.

Sunday, June 10, 2012

Thornleigh Brick Pit Exhibition

I managed to get to the Epping Club exhibition on Saturday and was pleasantly surprised by the quality and the number of new layouts on show.
Of course there were also the commercials to visit but I had to restrict myself a bit this time as Chris is not working due to her bad back problems. I picked up a pack of Austrains CWs and two of the Andian lever frame etches, a two lever and a three lever frame.
Well, I took a few photos while walking around and meeting people so here are a few of layouts that particularly caught my eye.

ARAKOOLA - A 7mm layout, very nice and not possible to all of it into the picture, there is a little more to the right.

WYEE - Very nice, there is more to the left of the first photo.

BOOROWA - A well done implementation of the scenery leading into Boorowa with photos of the real locations. The bridges need to be greyed up to represent old timber but still nice. The station area was highly compressed but this was likely done so that the interesting approaches could be modelled and space may be limited where it lives normally.

BULLENBUNG CREEK - A delightful, less is more, fine scale layout with a number of those quintessential NSWGR infrastructures features we love so much.

YENDYS - If you read YENDYS backwards you will understand the name. I quite liked this suburban themed layout which surprised me as I don't have any real interest in the Sydney electrics. You need to read the sign to the left of the road that is blocked by the police in the first photo then move onto the second. While the flooded creek is a bit 'cute' it is done very well. The street of flats and the shops also give a sense of perhaps a North Shore station. There is another half of the layout with an industrial theme to the left of the first photo. Over all well done.

GEOFF KNOTT - Of course you can't go past Geoff's work. Geoff and co. were running a scenery clinic for the kids and I saw several proud young ones walking away with a small diorama that they had made with guidance from Geoff and his friends.

AUSTRAINS - Finally, here are a couple of not too good photos of John Eassie's SRC, ICV, MV and LV wagons. Unfortunately they were at the back of a layout opposite the Austrains stand and with the barrier and gap to the layout front it was tricky getting a good photo.

I hope that you have enjoyed this rather disjointed view of the exhibition.