Currently I am picking up a replacement double shaft motor. Being physicist, I like to do things analytically. I have measured existing Mehano motor 12V unloaded frequency (200 Hz = 12000 RPM) and gearbox ratio (8.5 to 1). I haven't (yet) measured motor power though, because this is rather a complicated procedure. Since Mehano model trains have low torque the idea is to reduce motor frequency and/or increase motor power (power = 2 * pi * frequency * torque).

There is a plenty of inexpensive motors on EBay; frequency is always specified, but there is no specification on motor power.

**I have realized that those modern motors are much smaller than the fourty years old ones (three to four times smaller in terms of volume), but I assume that due to stronger magnets and more precise design their power might be even higher. Is this assumption correct?**

Second, despite most motors have frequencies above 10000 RPM, I found a few with frequencies between 5000 and 10000 RPM.

**Which frequency would be most appropriate if the gearbox ratio is only 8.5?**

Thank you for sharing your experiences and giving some advises.