The hourly wages in Switzerland are at least 2x those in Japan, and Swiss people generally don't like working outside normal working hours, so getting 10x workers at night is not very feasible.
You can get as many workers as you need, for a price.
For example, got a 2 day window at Christmas to perform a rail upgrade? And overrunning on time costs thousands of pounds per minute? Just show up with a large workforce and lots of spare parts and equipment.
The downside is you end up paying for things like having a couple of diesel mechanics on site just in case a backhoe breaks down. Maybe none of your backhoes broke down, and you paid for 2 guys times 48 hours times 3x their normal hourly rate, just to sit in their truck.
Of course, overnight work does tend to get noise complaints from locals - no amount of workers will solve that!