The good news: It is significantly less of a very bad thing when this happens to trains than to planes.
The bad news: We don't have running water in the toilets.
The good news: This Girl Scout is prepared! My first aid kit, including hand sanitiser, has made me popular in my coach.
The bad news: We are clearly going to be stuck for a while, because they've started giving out free bottles of water.
The good news: We have water!
The bad news: We are stuck until the "recovery locomotive" arrives, and even when it gets here, there will need to be a lot of assessment work and time-consuming maneuvering to actually make something happen.
The good news: There's a recovery locomotive on its way! (A recovery locomotive! I feel like I'm in an episode of "Thomas the Tank Engine"...)
The bad news: Our recovery locomotive has apparently become lost.
The good news: Such things lead to really great statements from British transport officials. "We sent an engineer out fifteen minutes ago to walk the locomotive in; however, it hasn't shown up yet. We're not sure where it is."