I did it with two 20kg bags --plus computer bag-- and got an intense 30 second workout, during which I pondered how the Airport Express planning committee could have possibly overlooked this obvious issue (i.e. $x billion project, $xxx,xxx elevator). Incidentally, San Yuan Qiao Stn. does not have the same problem.

I can't really recommend a subway xfer in your case because you'd need to do so twice... and still might encounter some stairs.

Now that I think more about this, since you're flying into T3 -- which adds an extra ~8 mins onto your train journey, I strongly advise you to grab a taxi.