Train tracks are actually very hard to sabotage, the US did a lot of research on that during WW2. You can take out a huge chunk of track before anything derails. Sabotaging the safety equipment is easier but with today's tech you can switch to GPS trackers on every train.

Data centers might be easier but

a) Will have a lot of security. It's much easier for somebody with money and connections (and now even intelligence+knowledge) to assembly a defense force than it's for a ordinary people to learn how to make proper molotovs, let alone learn how to shoot. And they will know when it's coming because even today's LLMs are good enough to surveil the entire internet.

b) I don't think they burn that well. When Ukraine strikes oil depots or warehouses, you can easily find images of them burning. I haven't looked particularly hard but images of droned data centers burning are quite a bit rarer. (I haven't seen a single one before actively searching, they do burn, but that's with military grade explosives.)