By request, I took a look at this map to give some feedback. I'm approaching this feedback from the perspective that these are the changes I would likely make to the map if I was to take it over. This is all theorycrafting and according to my downloads folder I haven't played the map since a2, so I could be totally off base.
I would try to turn this into a harder choke. Right now you're doing a lot of sightline management around the point with tall walls and that whole gameplay space around the tracks is awkward as a result. I think it would help to instead change the path of the payload and the surrounding geometry to block off the sightlines that cross the entire open area, segmenting it into two separate areas. This will free you up to make the gameplay space around the second half of the cart more fun, and will also help with pacing, allowing red to regroup after losing the forward hold, and allowing blue a more secure forward hold.
On a similar note, I would axe this route entirely. That building is pretty powerful for pushing the point and blue shouldn't get it for free. Instead, they should earn access to that building once they have successfully pushed up to the new choke I'm proposing.
Also, figure out where to put a sentry nest. Here's a rough idea. You might need to rescale some of this to make it feel right, especially with sightline management.
Blue generally gets the stretch of cart path immediately following a control point, which I've circled. Once they turn the corner, that's the first opportunity for red to establish a new hold. To that effect, I would get rid of the flank on the inside of this corner entirely. It allows players on either team to bypass the corner choke, which either means red will have a hard time establishing a forward hold in this room, or red has a route straight back to the point that they shouldn't be able to retake.
Also, removing this route will free you up to alter the scaling of the layout.
I'd also axe this route. It's another weird choke bypass. In general, it's better to provide options by allowing multiple angles and routes in one large gameplay space, rather than having flanks that entirely circumvent that large gameplay space. Red's best strategy is to spam the hell out of the flank so nobody can come through, because if blue players
do come through then it's an unfair angle on red players focusing on the cart path. It's not fun gameplay.
Make this area bigger and more interesting. What geometry do I have as a player to make use of when fighting enemies? Not much. Where does the sentry go? Where does the bulk of red team huddle up and fall back to? I think the answer is that red huddles up in the high ground corner area, which I don't think is a very fair area because its high ground only accessible from behind the control point. If you need more room, consider elongating it like this and reworking how the cart enters the area:
I think C is probably the strongest part of the map. This corner feels like a classic payload choke - temporary forward holds for red, a single simple corner with no flank to bypass it entirely, and one large flank that allows players to duke it out in a more open deathmatch area. I'd just remove this door, try to simplify/consolidate some of the interior routing to the flank area, and give a more protected place for a sentry.
I'm too tired to analyze D. I need to make dinner. This is probably plenty to work from. Hope it helps!