Pros: This is the first payload map I have ever seen with a train.
Cons: It's horrendously short, and red's breakable glass windows make it so that nobody on BLU can get to the train because RED snipers keep fucking with BLU when they leave the spawn by sniping out of the glass windows.

Pros: - fresh/new idea for payload
- simple layout of map
Cons: - a veritable mix of tf2 and hl2 models and textures looks odd and out of place.
- a complete lack of flanking options for blue leads to red snipers having a field day between points 1 and 2 (especially after the train has gotten to point 2, as there's no longer any cover at all)
- the train never recedes as a standard payload would. receding is important as it keeps the bomb at whereever the front line is, and lets people feel they are making a difference when they touch it.
- the carriages and train can trap people when they turn corners. i'd suggest looking at the key values and flags of the bomb cart and it's entities in a decompiled badwater or goldrush in order to see what is needed.
- the final explosions feels very lackluster. consider a large explosion that vaporises all the carriages.
- the enclosed carriage is a nuisance to get into. consider making the doors bigger
- although the blue spawn is interesting and spacious, the red spawn is VERY cramped.
- red windows have breakable glass. this lets red snipers attack blue from within the spawnroom (making them VERY hard to kill unless you are a good sniper yourself).
- the red spawn points face a door that locks after blue takes the 1st point. the annoying thing is that this means people spawn and have to do a 180, go upstairs, and get out of the door on the other side.
- the HUD being broken - i'm guessing it's because you made each carriage it's own train, thus the HUD is receiving 3 inputs of train position simultaneously.
i'd suggest referencing pl_frontier, which has a train+carriage and has no problems with the HUD.
- the train does not kill sentrys/teleports/dispensers that it runs over. at one point this led to me having a level 3 sentry that could not be sapped or shot at but could still shoot and damage the enemy.
- another con: in certain parts of the map, the skybox shows up in odd ways (i.e. making it look like a giant hill is right in front of you). this can be fixed by lowering the areas in your skybox that overlap the corresponding parts of the gameplay map.
Improvements: unfortunately there's a lot of work to be done, but i think if you take the time/effort you could have a very good/fun map here.
Notes: don't use so many feedback options, not all of them are relevant to the map, and most of them overlap a lot