It's available from 2027-04-01 to 2027-05-01, so basically deconstruction will be done during April. The bridge seems to be legit from 1876. Local news says they'd rather sell it to someone for cheap to support circular economy than throw it into the trash. https://www.tagesanzeiger.ch/sbb-verkauft-historische-brueck...
You might be able to make a good deal here, buy a bridge for 100 bucks.
But please note that the bridge will be available without the guard rail / fence, parts of the concrete might be missing, and the rust proofing needs a refresh!