How big are the luggage lockers at Oslo's central railway station?

All being well, I'm going to be having an 8 hour layover in Oslo next week. I'll be changing between airlines and between tickets, and I won't be able to check my luggage through. Given the length of the layover, I won't be able to re-check it on arrival, so I'm pondering what to do with it during that time. My current plan is to hop on the train into the centre of Oslo, and do some sightseeing, but without the luggage!

The Oslo airport website gives details of their left luggage, but it's priced per item so for 2 bags for >5 hours would be a moderate cost.

The NSB website says that Oslo Central has luggage lockers, but not how much nor what size. This tourist website mentions prices for the lockers varying by size, but doesn't mention the sizes.

Assuming my bags do fit in the largest locker in Oslo Central, it looks like the cheapest option is to take my bags on the train, pop them in a locker then go sightseeing. However, if it turns out they don't fit, it's then a bit late to leave them with the airport left luggage!

So, my question is then, how big are the lockers in Oslo's Central railway station?