I've read through Julian's and the helpful posts on the early version of the loco (from 2022), but I'm still not sure what I can do about the couplings, which will not engage with the current PECO couplings. The couplings are not in the right plane, but also the bit that sticks up (technical term) is pushed away from engaging with the loop on a vehicle. (This happens even when the cowcatchers are removed.
(I have to won up: I bought the loco when it first came out, but haven't tried running it with coaches until now.)
Has anyone found a simple solution to this problem? Do any of the alternative couplings available on the market work for this loco?
Russell
Took a little while to work out that it was my (Julien's) post rather than our esteemed Chairman (Julian). I suspect that a spool chukka had a hand in that!
Not having one of the locos myself it's a bit difficult to come up with a definitive answer, but from your description I suspect that as the heights are wrong then the springing on the coupling / pony truck is being pushed by the coupling loop on your stock rather than it dropping over the pin (what I assume to be "the bit that sticks up"?).
You could try reprofiling the Heljan couplings with a file - I'd suggest reducing the height of the top of the pin so the approaching loop can pivot up and over it, then reshaping the pin both at the front - you need a slope that the approaching loop can easily slide up - and the back - ideally there needs to be a little back rake on this face (the tip overhangs the base at the back) but vertical is just as good, you just need to avoid having a slope that the loop can climb back up and allow uncoupling as the train is pulled.
However, an easier alternative is that I think the Heljan locos are fitted with an NEM pocket (the coupling clips into a socket on the pony truck). Other NEM couplings should be easy to fit in place of the Heljan ones, but given that the height is the issue it may the the pocket is also too high (so replacement Peco NEM couplings also end up too high!) but if you used the Greenwich NEM couplings * then as these are etched brass they can be 'tweaked' up or down to get to the correct height.
Talking about couplings it's probably a good idea to get yourself some form of gauge. I have one of the cast resin blocks from RT Models (NGWC010 (https://www.rtmodels.co.uk/rt_models_018.htm)) but I also note that ST Models have introduced a 3D printed gauge (https://stmodels.sumupstore.com/product/greenwich-coupling-height-gauge) (but I haven't tried one of those yet).
Hope that helps,
Julien
* Edit: The Greenwich couplings for NEM are "CPL3". Light Railway Stores (https://www.lightrailwaystores.co.uk/collections/gdngrs) shows them as out of stock but the Dundas Models website (https://dundasmodels.co.uk/webstore/index.php/hikashop-menu-for-module-108/category/505-greenwich-couplings-accessories) shows them as in stock.
Many thanks, Julien (sorry about the vowel). On closer examination, with a photo taken yesterday at 'ground level', it does indeed seem to be the height, and I'll try the Dundas Models site as a source for the Greenwich coupling.
Russell