Which dcc.

I will add to the above good suggestions, worth visiting a DCC specialist retailer, either at their premises, or at a show if these become operable. (If you are anywhere in East Anglia, hearty recommendation for Kevin Dickerson at Coastal DCC, nearest such specialist to my location.)

My frank opinion on RTR models of the 'Triang epoch': unless they are superb runners on DC, don't bother. DCC decoders cannot fully overcome the mechanical shortcomings of poor torque and direct worm drive on an axle, and also require good current collection which pick up from mazak wheels doesn't reliably deliver. (I have my 'best XO4 ever' in a 1950s Princess worked on to add tender pick-up, with an expensive 2A continuous rated Zimo decoder to cudgel decent running out of it, for old times sake.)

Start with a modern low current consumption can motor on a multistage gear train RTR model which the economically priced Lenz standard and Zimo MX6xx decoders will operate beautifully: effortlessly offering the fine control that in the past required the likes of Portescap mechanisms and Morley and similar brands of controller.

The pick of Lenz decoders is the 'standard'. Typically a pound or two cheaper in the UK than the Zimo MX6xx series but only available in wired 8pin, will operate any competent mechanism beautifully. That's my 'default' decoder (I regard DCC as a utility and lowest price is what I want for utilities) because I still hard wire about a third of my purchases to overcome factors such as manufacturer ineptitude in decoder socket positioning.

But with manufacturers at last getting with the programme of neat and tidy decoder socket installation in appropriate locations, Zimo's MX618 and MX638 (Next18 and 21 pin) are increasingly purchased.

It's all 'invisible' in operation; the mixture of various Lenz decoders, some near 20 years old, earlier Zimo MX63 and 64 and their current decoders, and the long withdrawn Bachmann badged ESU v1 lokpilots all perform well. All of these either come with or can be configured with the Lenz F4 suspend CV's 3 and 4 feature, invaluable when moving locos off scene, as I typically apply values of 60+ to reproduce the high inertia of rail vehicles.