For the decoders, I chose ESU’s SwitchPilot Servo model, capable of driving four servo motors.
Regarding the servos, there is good and bad! I had started testing with a GWS Pico + servo. Satisfactory tests, but a rather high price (almost €20).
So, I found Tower Pro SG90 servos on Ebay Hong Kong, that costed me less than €2 including port, by 10. But here, big disappointment: even in no-load condition, they growl, do not hold their position, warm and are finally impossible to set correctly. Obviously not made to operate at low speed. However, a quick visit on the Internet gave rather favourable opinions on these servos.
Last attempt at date: Pro-Tronik 7450 NG-D V2 servos designed in France, but manufactured you know where, bought from Weymuller’s, at €5 piece (there were cheaper sellers but with higher shipping costs). Mixed results. They work well, allow stroke and speed adjustment without recoil, but sing at the end of the stroke (I say sing and not groan because the sound emitted is much less impressive, and more musical, than that of the SG90). And I found a means to shut them up!
Conclusion: regarding servos, there seems to be a correlation between price and quality. Remember that the €20 GWS Pico +, which I had mounted on a test board, gave satisfaction, very slow movement possible, no grunting or whistling at the stroke end. But then, we’d better buy the ESU servos priced €13.50, which we can assume perfectly adapted to our needs, and supplied with a fastening system.