Downloaded and ran through your map:
-The map name is not versioned.
-After setup time a tiny black line remains under the door near the cart.
-It would be nice to have some tracks for the cart to ride.
-The area just outside BLU's first spawn feels like there should be RED players. Perhaps remove the doors on the spawn itself, or just remove the side doors. If you don't know what I mean, it's the gravelpit-style spawns.
-The doors you cannot walk through should have a hand on them until they are available.
-There are a few areas of displacements you cannot climb. You should smooth those out.
-There are only two routes for BLU to enter the first area, normally there are two major routes and a minor, or one major and two or three minors.
-A lot of the indoor areas have really low roofs, with lights you bump into. This really give an advantage to soldiers.
-I would limiting the caution strips to rollback areas.
-If you want the windows in the red building in the second area to be used for snipers you should use a badwater-style one glass pane removed element. Otherwise you should be able to climb out of them.
-The room full of turbines may be better suited with spy-tech instead.
-Have you considered a tiny trickly of water flowing from the sewer drains to a drain of some kind?
-There's a lot of use of a very white railing which doesn't fit your map's color scheme.
-I like to use the overlay tool rather than the decal too for signs because some players disable them, but it's your preference.
-Perhaps a sign that raises and lowers itself should be in the spawn so you know which way to go.
-There are no ambient sounds on your map. Don't know if you were planning on adding any.
-There are a lot of short corners you may be unable to make using tracks.
-The texture use makes the different areas look the same (all the buildings look alike).
-The cart travels through a lot of cramped indoor areas. It would weaken the power of sentries, but increase pyros, soldiers, and demomen.
-Is there a better route than through BLU's spawn to move the cart? It seems like a bad area. Just like another setup time for RED (unless that's what you want).
-Your entire map still renders. Place some area portals in the doorways. This map shouldn't be too hard to optimize, it's very sectioned-off.
-Light shouldn't come from lights that look like they're off.
-The cart can roll back in the roll forward zone.
-Why is there a roll-forward zone on the third point?
-What is your dynamic element?
The map is pretty if a bit dark in places.