On the question of TT300s, I've bought nine of them over the past year or two. Of these, one had an internal switch that would only throw consistently in one direction, thus causing a short in the other direction. Apparently, this was known issue and I was recommended to ease the slot on the underside of the pc board where the operating pin protrudes. This didn't really fix it and it was not until I stripped the whole thing down and fiddled with it that I managed to get it to work. At present, that one is sitting in my spares box.

Yesterday I powered up the layout after a few weeks without use and found that another one was not working at all. At present, I don't know what the problem is. Hopefully, it is just a loose wire but I won't know until I get under the layout and poke around. Unfortunately, that turnout is not very easy to get at without separating the boards.

As you might imagine, TT300s are not my current favourite piece of kit. That said, they work well when they are working.

I was also interested to see your approach to isolating the frogs. I've been doing much the same with Peco OO9 turnouts after I found the alternative of replacing the metal joiners at the flexible heel with insulated joiners was not proving to be as reliable as others have suggested.

Nick

Thanks for your comments Nick, much appreciated.

Yeah, there seem to be various ways to isolate the frogs, but in N most really affect the point visually with the resulting gaps looking too big. I found the advice to use a jewellers saw on this forum and was very happy with the result.

A quick update on my second apparent TT300 failure. I eventuallly got under the layout to remove it and found that there was nothing wrong with the point motor. It was just a stuck tiebar, so the motor would not move. So, for now, TT300 are back in my good books.

Nick