Tuesday 7 January 2014

Who Let The Smoke Out...Part 1

All,

Here we are with Christmas just a memory and January 2014 in full swing.  I spent a bit of time on the layout in the last few weeks in amongst juggling customer's jobs that just HAD to be completed.  Following on from the last post I have now installed all pointwork and associated tracks at the down end of Fish River yard.  All point motors have been installed and all wiring was finalised last night. Lastly was the "power in" link to the control panel and all was in readiness to "liven" up the newly installed panel and the now complete yard.  It always amazes me the trepidation I feel when a section is completed and it is time to introduce power.  It should be a time to rejoice as all the blood, sweat, tears, profanities and stiff joints that have been invested should pay dividends and the enjoyment of running a train or three should be just around the corner...Right???.

When I completed the Up end of the yard and associated trackwork and control...I double, triple checked every joint and connection and then went over everything with a multimeter to ensure all was as it should be before livening things up and with this approach it all went remarkably well.  With the down end of the yard I foolishly threw caution to the wind in some instances and decided that as this end would be a mirror image of what I had already done and if all methodology was copied then there should (in theory) be minimal issues.  I did visually check everything and then hit the on button...

From the instant power was introduced it was clear that a short was occurring and the NCE system went into protection mode...power was turned off and smile turned to frown. An hour long inspection was undertaken in an attempt to uncover the culprit.  Nothing appeared to be wrong so I isolated all point motors and reintroduced them one by one in an attempt to nut out the issue.  During testing of the second set of points and with me under the layout I failed to notice a short and only became aware when I could smell something was not right...Another panicked shutdown and another inspection to find the source of the "leaking smoke". After another 15 minutes of head scratching and bewilderment...I found the source!!!.  The frog polarity wire had burnt the underlay on this set of points and closeup inspection revealed a partly melted sleeper.  My initial thought was that while fitting the points the frog polarity wire had somehow become dislodged from it's housing and was now in contact with both running rails....but upon lifting the point it was fairly obvious that sheer carelessness was the gremlin.

It may help to explain that I use Peco code 75 "live frog" points universally on the layout and also conduct the usual makeover of each point to make them DCC friendly and because I utilise Cobalt point motors ( and for appearance sake) I also remove the bulk of the throwbar detail, over centre spring and housing etc.  I then replace all removed sleepers with copper clad circuit board type sleepers.  I have been trapped in the past by not gapping these copper clad sleepers prior to installation and they have only been discovered during routine inspection before powering up the new section.  In this case this issue was not the culprit...  The issue was that as part of the DCCising of the point I had not removed the factory fitted links and as such with the modifications that I had carried out and the non removal of these links... the point was now had an inbuilt short circuit.... Luckily my stupidity was only discovered on 2 sets of the 8 that had been laid...

The story does not end there and Part 2 will complete the saga of Fish River yard...

For those unfamiliar...I have fitted soldered links that are visible centre right...which in order to operate correctly require the links visible at left to be removed... ( This shot was taken after removal )
          

Burning of cork roadbed and underside of sleeper...with frog polarity wire disappearing under the baseboard...



Damage to underside of the point....

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