Heyo, we played this the other day. Was pretty fun overall, but a bit rough in general. Comp players are very quick to notice things like floors that require you to hop or lips that you can get caught on, so you'll want to clip those things even at this stage.
General comments. Some parts of the map feel a bit cramped. The middle point especially feels quite hard to fight in without getting demolished by spam and jumpers. You might want to consider widening it a bit (maybe 512 units or so). Obviously thats likely to change things a bit overall, but i think it would make the middle point much more fun to fight in, and balance things with regards to the other points. Might also allow you to get rid of the longer train track area. On both sides it stretches quite a bit out, meaning that combat can get pretty distant.
You should probably label the different areas. Its much easier to direct traffic if you know the names of the three areas (A for the valley, B for the middle, C for the train yard). Train is at C vs train is at trainyard thing on right. Also helps map makers telling you what to change etc.
Spawn should be a bit bigger. If you adjust the size of middle you can make the spawn building larger and give players a better idea what each door does. Also, the arrow signs are great and all, but I'm not so sure you'll need them for comp. Its hard to say, but I'm guessing people should be able to keep track of the trains location through communication (train is at C, train is at B, just died train moving from B to C and so forth). But its up to you, just feels a bit cramped in spawn room with those signs in the way of jumps and rollouts.
Ammo should be moved around a bit. Maybe small ammo in the main fighting areas, but the mediums at the connectors?
Okay, each point itself.
Trainyard: Feels okay, maybe a bit cramped some times. The chickenwire fence thats above the main door is a bit weird. I'm not sure why its there. If its to stop bombing the door, I don't think it does what you want, and its going to give someone a weird spot to hang out on top of. The bridge is okay and kinda fun to fight on, but it takes a long time to get up there and it is pretty high up. You might want to make the ramp system that gets up there a bit more concise with less chance of falling off. I fell a couple times inside the tower and that wasn't much fun. However, you'll have to be pretty careful about that. Sniper sight lines from that point to B and so forth are pretty strong, and if you make the ramps up to the bridge too fast, the sniper can get up there really quick and rail off shots fairly quickly. Might want to put some small healthpacks somewhere here. The mediums are great, but they are really far away, and i felt like I always had to fall back even with only slight damage.
Middle: Like above, too small. Fighting is pretty intense here, lots of people jumping into each other. If you make it larger, a small health pack in the main room might be good. Maybe put it underneath the central platform with a small ammo.
Canyon: Okay, canyon feels really weird. I like the low and high area idea, but I feel like the lowest area is TOO low and its no fun to be down there. I recomend you stick with only two levels of ground heigh, and cut the lowest one. I would also like to see that the connector from spawn be put so that you can walk back into it. Its no fun to run to that medium health and not be able to get up back to spawn.
Was pretty fun to play. Some people weren't to hyped about the gimmic but I felt like it played okay. You just need to work on the layout a bit, and it could probably end up being pretty slick.