Team Fortress 2/plr pipeline

Pipeline is a racing payload map, where two teams compete to get the patload to the enemy base before the other team. Unlike other payload maps, the cart does not return after inactivity; instead, it rolls backwards on specific inclines.

Stage 1
Stage 1 has two access routes; through the main area, and through a one-way door that leads behind the enemy base.

Demoman
Demomen can spam grenades through the openings above the central gate during setup time.

Stage 2
Stage 2 has two access routes. The first is through the main tunnel, and serves as a choke point for both teams; the payload must go through the area, and it is easily defensible by both sides. The second access is more suitable near the end of the round, and it is located at the top of your second floor. It is used to flank the enemy and gives a faster access route when the payload is near the checkpoint.

Engineer
The engineer needs to seal off the main choke point with sentry gune. While this has a side effect of forcing enemies through the other access route, it is preferable to having the payload coming close to your checkpoint.

Stage 3
The final heat has the two payloads side-by-side, and you need to get them to the top. There are two available means to reach the rails, leading to the base of the uphill ramp, and the second behind the ramp to the final point.

Engineer
The engineer is not an effective choice for this heat. There is not enough time to setup the sentry gun in most locations, and the open arena would allow the sentry to be destroyed at long range.

One area where an engineer can set up a sentry is at the very top of the map where the winning cart will eventually end up. If an engineer can get a dispenser built in the secluded rooms at the top, then he has a real chance of getting a sentry gun up as well. This will make the map very difficult for the opposing team to win.