score:12
Lucerne has an old city and a new city part, split by the river running through it. On this map, you can see the pink "Altstadt" (=old city) where the river ends in the lake, at the centre. The main train station is just south-east of that, across the river.
I would consider the Altstadt the center of the city, others might consider one of the bridges the center, or the roads along the river just before the lake starts. In any case, I would take a look at the size of the city. It's not very large and if you are willing to walk a couple of hundred meters from the hotel to the station, you will find out that you will not have a considerable distance from any of the points mentioned above.
Upvote:4
On google maps, this point for instance is in the old town/city centre.