Duplo Deluxe locomotive needs more power

[Need more power5135c01]

Hello all, 

I recently added to my kidd duplo train collection with a secondhand set. The red duplo train does not seem to have as much power as my original. They are the same part (5135c01) but one cannot get up the hill even without any extra carriages or blocks.  I am happy to tinker, and i got as far as making sure all the gears are in tact,  but did not go futher. 

I contacted lego company and they think i could try replacing the motor.  Has anyone had this issue and resolved it? Or has anyone been able to super power a duplo train. Please help if you can

[JopieK]

What kind of batteries do you use? Most rechargeable batteries are 0.3V less than alkalines (1.5V vs 1.2V) so that is 1.8V less for 6 batteries and you would notice that in motor power. Maybe that is not it but it might be something.

[Need more power5135c01]

Thanks for the tip on rechargable - alas i do not think it is the culprit,  i have tried brand new single use and fully charged rechargables. Lego corp suggested a motor replacement.  I would love to hear from anyone who has had experience with this