The C13s are in the “Wait till Autumn,- Dave” box but I decided to get down to solve the J10 hiccup running

It was indeed the split axle that had failed so a new one was made but when back to trial running stage there was still a tiny jerk when slow running. Not only that but occasionally there was a short which shut down the DCC – Bu****!

In fact it was the shorting that gave me the answer, because while looking for were this occasional short circuit could be occurring I noticed some bright brass on the valance bottom edge just above a centre driving wheel. Investigating how this had happened showed that the crank pin nut just brushed the bottom of the valance, causing the perceptible jerk when slow running but not noticed with faster speeds. It was also the position of occasional short-circuit. A strip of 0.010” plasticard raised the running plate minutely and both problems were solved.

However!!!!! Test running on ‘Bowton’s Yard’, (where I have a double slip followed immediately on one route by a B6 turn-out, all on a radius of about eight-ten foot) showed the loco derailing at one of the double slip crossings in forward direction but OK in reverse. It performed well all over the rest of ‘Bowton’s Yard’. This suggests that the error is at the double slip crossing but I’ll check the loco wheels first.

Well, the front axle B-B was perhaps a bit wide but in tolerance, so too were the other axles. I removed the front axle and mounted it between centres in the lathe. There was the tiniest bit of wobble in one wheel but I’m talking in terms of hardly being able to see it; - perhaps 0.002” on circumference, probably less. That should be OK! Therefore it must be the crossing.

Track gauges out and check the double slip. Nothing untoward except a touch of tightness at the checkrail of that crossing but the gauge suggested that all was as it should be.

Run other locos through slip; no problems with the 0-6-0 tanks but they are a bit small, try the B1; no problem. It must be the J10 but what the H*** is it?

I tried running the loco fast, slow and in between but it came off. The front axle always rode high at that crossing. That cannot be possible! The B-B is correct; the track is correct. But it still came off.

As with the ‘catching the valance’ problem this too was solved by accidental visual input. I noticed, as I put the loco on a flat surface, that the centre wheels touched the surface first; they were lower than the front and rear wheels and under downward spring pressure. This caused me to put the loco on the double slip, just in front of the problem crossing, and finger push it through, but very, very slowly. There was a rock around that low centre axle; the springing was too harsh!

Sure enough, a slight tweak on the cantilever springs produced the answer. I also adjusted the axle retainer such that the centre wheels were unable to travel lower than the other two axles.

The J10 now covered all of ‘Bowton’s Yard’ several times, and at all speeds between creep and “Gosh I didn’t know J10s could go that fast”. All was well but just occasionally there was hesitation or jerk at that crossing.

Crossing checked with gauges again and all OK but I decided to ease that checkrail where the gauge felt a bit tight. It was a distance imperceptible by eye; the minutest of tweaks but it did the trick.

All this frustration would seem to have been due to high end tolerance on one thing and low end tolerance on the other; something that the “plus or minus” system is supposed to defeat. Perhaps it’s my poor skill level!

My frustrations were not at an end. The past few days of work had been aimed at getting the J10 to stop derailing at that double slip through which my other locos had for years travelled without problem. I had carried out adjustments to that slip therefore I need to check if that has effected running of all my locos.

The K3 repeatedly derailed!

My S4, K3 (I’ve an EM one too!) has always been a delightful runner at all speeds both on my layouts and as a visitor to other layouts. “What is going on?”

I tried it all over the layout and it was falling off left, right, & centre. I’ll tell you why and how it was corrected next time.

Meanwhile I wish you less frustration with maintenance than I’ve had recently!

Dave