600Kg surely is a weight. Anything other than dead flat and I wouldn't be able to move that without real difficulty.
For a planer, take the attached as a suggestion. Hot rolled Parallel Flange Channel can be bolted to the sides or underneath the base of the machine. Fit high load castors, or fixed wheels at one end and castors at the other. Most importantly, also fit it with screw down feet to lift the castors off the ground and stabilise the machine every time before you use it and to unload the tyres while the machine is parked. No cheating.
I set this little PT255 up as you see because I needed to roll it out of my workshop to use. There is a slope so even this little thing is hard to push back indoors. But put a 10 foot hardwood plank through a little machine like this with a small base without the infeed and outfeed roller stands setup just right and a heavy length of hardwood can apply enough leverage to rock it.
Lesson learned. Make the base channels longer and add screw down feet.
With a 600kg machine, planks will not be rocking your planer, but you should add the feet as well as castors for levelling and absolute stability.
Also, keep an eye on the machine in case moving it twists the alignment, even if only a little. Planers aren't meant to be wheeled around.
View attachment 180109