I use TCS DP2X-UK decoders in my Heljan locos. I've tried them in 47s, a 33 and a 26 with excelent results every time. These are rated at 1 amp continuous, 2 amps peak.
The first Heljan loco I chipped was an early 47 and I used a Bachmann 3 function which got rather warm and kept cutting out. I swapped for the TCS and everything was fine.
I have also tried a Bachmann chip in the 33, it didn't seem to be over taxed like the one in the 47 but wasn't as smooth pulling away from a stop as it was when I tried a TCS.