In Finland, the only difference between "high-speed rail" and normal trains is that one of them is called "high-speed" while the other one isn't.
Seriously. There's 75 whole kilometers of track (Kerava–Lahti) in the whole country where the "high-speed" Pendolino trains are even allowed to go faster than their InterCity counterparts, and even then they only go 20 km/h faster. At other times they go exactly as fast, cost as much, and stop at the same stations. And they're more cramped.