Remember that engineers can build underwater. Be creative! One very effective strategy is building a teleporter exit and/or sentry gun in the water in the enemy’s moat when pressing on the second last point. And remember, an underwater dispenser heals you faster than a lack of oxygen hurts you!
If well defended, the second last point can often be difficult to capture. A very effective method of breaking up the defence is an übercharged demoman rush, as mentioned above, chucking a couple of sticky bombs on every sentry gun and exploding them. Following that, explode as many enemies as you can, then have your team charge in behind you. They should now outnumber the enemy but a significant margin. Sniping (soldier, sniper, even demoman) from the top floor can also help distract the defence’s focus.
If your opposition is managing to push you back and they take the middle control point, don’t give up on it. Wait for an opportunity when they attack in a wave and more of them die than you, then move up and attack the middle. If nothing else it will take some pressure off your defences, and the worst that can happen is you die and respawn. Try and get your team to push up with you – once you get inside the train yard it’s relatively easy to defend, with only 2 readily accessible entrances.
In fact, Well is a map built around rooms with only two entrances/exits, at least two that people will often use. Occasionally there’s one or two more stealthy ways around, but only spies tend to use these. Therefore the effectiveness of demomen cannot be stressed enough. Having 2 demomen plug up these 2 entrances (1 each) can all but completely prevent the enemy from launching any kind of counterattack. Sticky bombs at the entrances to the train yard and roller doors to the second last point are the best preventative uses.
Then again, these sneaky routes that people tend not to take translate to a way of getting in among the enemy without being spotted. If the fight for the train yard isn’t going as well as you had hoped, consider jumping into the water hole on the enemy’s side, swimming to the enemy roller doors and engaging the enemy from behind as they walk out, holding them up and giving your teammates an easier job of capturing the middle control point.
