Bayeaux to Lourdes
 

Is it possible to take a train from Bayeux to Lourdes for a day trip, I can't find this information anywhere else?

Lourdes in the foothills of the Pyrennes so I can't imagine a day trip there from Normandy. Both are in beautiful areas but ,perhaps, difficult to combine.

You can check train schedules here:

http://sncf.com/indexe.htm

Doesn't seem feasible to me, I did a quick search on a random day and for this route, you switched trains and stations in Paris. Total time one way was 12 hours.

What do you want to visit Lourdes for? It's a depressing place full of hospitals and tourist tat. Mugs go there in the hope of being cured but their cure rate so far is zero. People have even come back from there with diseases from drinking contaminated holy water.

Lots of nice places around Bayeux worth visiting. Try Deauville, Trouville and Honfleur.

Kaneda - lots of people go to Lourdes for personal or spiritual reasons. The OP asked if it was feasible, not be put down for having the desire to visit.