Whimsy sidings.

No, I’d suggest you go back and check the loco wiring - without a “suck eggs” comment, make sure no earths or bad contacts. If you have a volt meter with a continuity checker, see if you can test each wire up to the decoder (subject to how well they are shrink wrapped)

 

As they are both 'not dcc ready' Pete, have you checked to make sure both the motors brushes are completely isolated from the chassis? One side of the motor of each will already be isolated but for dcc, both sides need to be isolated. If you're still stumped and not in a rush, leave it until April 12th when we can come out to play again and I'll have a look for you.
Keith.

 

For the record if anyone is following this, the actual problem with Pete's 'Jinty' was the loco pickups. With many 0-6-0 loco's, to allow them to go around tight curves on 00 gauge layouts, the axles have quite considerable side play and to keep the wiping pickups in contact with the wheel backs they need tweaking to keep them against the wheels at both extremes of sideways movement. Loss of contact also encourages slight burning where the pickups touch the wheel backs and this can also give problems in maintaining a constant supply in the same way as dirty track or wheel 'tyres' and with DCC, the slightest 'stutter' in the supply can result in the decoder either shutting down or doing daft things such as a 'runaway'. Like Pete, I don't think the trapped wire was in itself a problem although it might have been problematic in the future. Unfortunately, since non-DCC loco's were never designed with conversion in mind, clearances in such loco's are often tight so it pays to take care with wiring on reassembly.
Keith.

 

I don’t think all decoders support DC running.
Some will actually do different things if detecting DC signals. Such as stop.. (Lenz decoders)

 

On the rare occasion I've had a short on the 00 gauge layout, my first step was to remove all stock from the tracks and go from there. It's a step by step procedure rather like when something trips the main RCD in your household consumer unit, you start by turning everything off (or unplugging), reset the trip and plug everything back in one by one. When the trip goes out as you switch an item back on, then Bingo, you've found it, so just adopt a similar procedure Pete. If you get stuck just give me a shout and I'll help if I can.
Keith.

 

Pete it may be time to go to dark mode

By this I mean turn the lights “off”, run a train over the track and look for a spark occurring as you have Keep alives fitted if a short occurs the NCE will trip but you Loco will / May have kept moving from the point it tripped the short circuit protection and the NCE unit eventually powers back up and the train starts again as it’s no longer at the short circuit location, hence the dark mode to see where the real issue started.


Another issue that can occur is the inrush current of a Keep alive with the low power 1amp NCE power cab, this often occurs when track is dirty and the Keep alive is working over time to keep the train running the power cab sees this higher current as a short and depending how capable the wall wart power supply is it may also start to become lazy, I’ve tested a few “power cabs” to find the 1.5 amp peak rated Wall wart is only capable of supplying a constant 0.3amps and a real peak of 0.5-0.8amps @12volts any higher for example like a peak draw occurs eg Keep alive starts to draw as well as loco moving and they fall over the voltage starts to drop ( to less than 10v) as this higher current draw demand occurs, = hand set turns off, don’t forget if more than one loco with KA on the track each KA will be recharging after a short even a micro short

It may be worth having a check of a few basics like the power supplied to the track vs the in put power supplied by the supply.
Using your Volt meter watch the track voltage for any drops or micro shorts = 0 supply , then set up and watch the current draw and see what the amps draw is while this is happening.

I’ve got a DCC concepts Alpha meter and it’s the perfect tool for quick diagnostics of these voltage / current draw issues as you can see both in near real time, I can highly recommend them. I’ve got one on the work bench and then one on each layout.
https://www.dccconcepts.com/product/alpha-meter-for-dc-or-dcc/

 

Good advice from Chris. I was also going to suggest removing all stock from the layout, disconnecting the track completely from the Powercab and doing a resistance test across the track, which should of course show no continuity just to ensure that nothing metallic has bridged the track at some point. As I know zilch about Powercabs, I assume that the wall wart that Chris mentions is one supplied with the Powercab itself, in which case I'd be looking for something with a bit higher current rating since with Stay-alive's fitted, you have got to allow not only for the current draw of the loco's but also for the current draw of the Stay-alive as it's charging. It's odd that although both loco's ran ok when I returned them to you, (and faultlessly on my Lenz setup which is very short-circuit sensitive) we didn't run them together on yours, only individually and they were not both on the track at the same time. Do you have any other 00 gauge DCC loco's that you could try? If not and you've still got problems I can always bring a loco over and try that. Let us know how it goes.
Keith.