how to get a heavy rucsack on?

I flew back to the UK this week and had a 70 pound pack. Carrying it was surprisingly easy, as far as commuting went. Airport to train, to bus, to taxi...
BUT actually getting it on my shoulders was the hard part. With there always being chairs in stations I could lift it on to them, then to my back. From the ground not so easy.
Anyone got a solution? I was thinking I could shoulder the pack then
add belt pouches to the waist belt with the heavy stuff. But ideally I'd want it on the pack itself.
qjs

My first thought was to reduce the weight, but I am sure you have thought of that already. If there is nothing high to place the pack upon, you can sit on the ground next to the pack, work the shoulder straps onto your shoulders, lean forward on your knees, and then stand up. A hiking staff comes in handy here, or better yet, ask the attractive lady standing by to give you a hand...

One method is to stand at the top of rucksack if it's laying down with straps up. Put arms through straps, and bear hug it. Then muscle it over your head and the right way up.

Other is to tighten you dominant side should strap, and loosen then other. Stand feet apart with fore leg bent so can pick up the ruck by the straps and sit in on your thigh, then get the dominant arm through the tight shoulder strap. Should be able to fish for the other lose should strap and get it on.

Set the pack on the ticket counter, or the counter or table at one of the airport restaurants, or on the hood/bonnet/trunk of the taxi? Or on a bathroom sink? Ask 1-2 appropriately sized people to help?
There are backpacks with wheels to pull behind as well.

Thanks Folks between those methods there'll be some way. I'm printing this page off and leaving it in the lid.
qjs

as an overnight backpacker, i agree with Ren as that works great for me. it's all in the balance. i must say that while trying to sit down with it on for a brief rest i have turned turtle once or twice - which is always good for a laugh.

if in civilization there may be something / someone to assist.

As someone who has spent a great deal of time carrying very heavy backpacks, I would suggest you really think about how much you are carrying and why.

Assistance is good, if you have some. Sitting on the ground and slipping into the straps, then standing up is a decent option. Slinging a heavy backpack can be problematic and even dangerous if you lose your balance.

As I understand he was not hiking. Just travelling with a backpack instead of a suitcase.

If I remember correctly, Colin Fletcher had a trick to assist in mounting-up a heavy apack. Checkout , The New Complete Walker IV.