Event has ended. Solutions are posted here.

I have just realised recently I have never made a giveaway train.
So I decided to make one, but I wouldn't be myself if I didn't make it a puzzle train :)
It took me much more time to prepare it than I thought but it's finally ready. So there we go...

It's a train of puzzles. It has exactly 19 wagons. Each wagon contains one giveaway. Some wagons are hidden well.
The journey is split into three stages between four train stations. Each stage requires a ticket that has to be found.
You don't have to finish one stage to get to another, but it should be much easier to find the next ticket if you do.

All giveaways are up till March 20th. If the puzzle turns out to hard at some point, I may or may not provide hints. However there already are some hints scattered along the way.
The giveaway links are always http://www.steamgifts.com/giveaway/xxxxx/ where you have to replace xxxxx with a unique case-sensitive giveaway code. Don't forget the slash at the end.
All tickets are to be redeemed at ITH: http://www.itstoohard.com/puzzle/xxxxxxxx/ whrere you have to replace xxxxxxxx with a unique puzzle code.

The prizes are: 2064: Read Only Memories, Dangerous High School Girls in Trouble!, Dessert Storm, DRAGON: A Game About a Dragon, Else Heart.Break(), Epic Battle Fantasy 4, Mahjong Deluxe 3, Mahjong Destiny, Puzzles Under The Hill, Rail Cargo Simulator, The Hidden Dragon, Thomas Was Alone, Ticket to Ride - USA 1910, Trainz Simulator 12.

EDIT 1: Changed the #6 and #7 entrance puzzle pictures to better quality.

Hint Pack #1:
Wagon #8 is at the end of the mad loop.
Wagon #13 is available after solving all three train station puzzles.
Wagon #14 seems hard to find, but it's not. Keep in mind, what's this whole puzzle about.
Keep in mind that you can find all tickets without solving any puzzles.

EDIT 2: Changed the #16 entrance puzzle description, to make it a bit more clear.

Hint Pack #2:
If you're a beginner, read the guide.
If you're missing some tickets check out my sg profile.
If you can't figure how to decipher the message at #7 entrance think what you see and what's this whole puzzle about.
If you're stuck at any ITH question read this page carefully. There's nothing hidden here, but there are a few hints above the hints section.

Hint Pack #3:
Tickets for Station B and C are hidden in giveaways I've created. These giveaways share a common theme.
Wagon #7 can be found by decypting a message with one of these tools. Keep in mind the puzzle theme and what's in the picture.
Wagon #13 can be found by combining three parts and decoding the whole.
Wagon #16 can be found by googling some of the keywords. Don't give up on first page of results. The answer is not a real transportation, unfortunatelly.
Wagon #19 can be found even without finding all the wagons. You can geuss the number (it won't be that hard after reading previous hints) or you can look for a pattern in numbers you have.

Hint Pack #4:
For station C you need two tickets, You'll find them in my old Trainz Simulator DLC giveaways.
For Wagon #9 you need to check out my ongoing non-private giveaways.
For Wagon #13 you need to decipher 5+5+6 characters long base64 code
For Wagon #16 you need Google maps. Find a way from Snowdon to Brecon Beacons
For Wagon #17 you need to click the bump link :)
For Wagon #19 you need To find the sum of numbers, where each odd wagon number is a multiplication of numbers from two previous wagons and each even wagon number is always 2. Or you can just get the sum from the prizes list :)

View attached image.