Trains has always been my favorite deck and I will always try my hardest to make them compete with the current meta.
Trains ALWAYS want to go second if you have the choice.
If you have to go first, Dragoon is your best option. It's pretty easy to get two monsters on board to make Verte with how trains work. Dora is your second best option if you have to go first (if you know they can out Dragoon easily). In some special cases you can even make both going first!!!
In a recent regional tournament I had a judge rule that Interrupted Kaiju Slumber WILL WORK under Barrier Statue of the Stormwinds' lock as long as one of the targets is a wind monster. So take that ruling with a grain of salt because that's not how it actually works. That makes Gadarla, the Mystery Dust Kaiju your best out to Floowandereeze at the moment.
- The Kaiju engine is to help break your opponents board by removing problem monsters and possibly getting you even more level 10 monsters. Three Jizukiru and Gadarla to help the chances of opening one of them, and only 2 Slumbers because if you draw one Kaiju you would make the third Slumber a dead card in the deck. One Kaiju card + Night Express Knight + Derricrane is usually enough for an OTK in most cases. Kaiju the problem, summon Express, Special Derricrane, XYZ into Gustav and burn for 2000. Then use Derricrane's effect to destroy the Kaiju. Overlay into Liebe, activate effect to make ATK 6000 and punch for game.
- Switchyard is your bread and butter. Don't have the level 10 you need? Just pitch what you don't want and add what you do. Switchyard gets shut down hard by Ash Blossom unfortunately; so you need to try to bait the Ash first if you really need that search.
- Switchyard + Pegasus +Bullet Train = 3 level 10s. Switchyard to pitch Bullet adding Derricrane. Summon Pegasus, activate effect to special Bullet from grave chaining Derricrane. If you already have those three monsters in hand, pitch Bullet to add Bullet, then do the combo again. Only this time you activate the second Bullet in hand for 4 level 10s. That's either a Liebe and a Dora, or a Dora and Dragoon, whichever board is stronger against your opponent.
- Try not to make both Zeus and Dragoon at the same time, they just counter each other and you'll usually end up sending your Dragoon to the grave when you don't want to.
- Urgent Schedule is one of the best cards in the deck. Depending how good or bad your hand is, you can easily end on a Liebe with Dora protection. Or, it'll save you during the battle phase by summoning two monsters (in defense) to absorb some damage. The two best monsters to summon off this are Ruffian and Bullet Train because of their end phase effects to get the cards you need into your hand.
- One funny combo happens when you have Switchyard on field, Urgent Schedule set, a level 10 in the grave, and a derricrane in hand. During your opponent's battle or end phase, activate Urgent Schedule to summon two monsters. Then, activate Switchyards effect to summon a level 4 and it becomes a level 10. Summon Pegasus making it a 10, then activate Pegasus' effect to summon the level 10 from grave chaining Derricrane so that Pegasus' effect won't be negated. 5 monsters summoned during your opponent's turn and they can't even Nibiru you (if you did it during their end phase). Make Dora first for protection on your turn, then do whatever combo you want that will hit them the hardest.
- Bullet Train and Ruffian are two very good cards you always want to send to the grave to get their effects. Ruffian gets you a level 10 Earth Machine from the deck and Bullet gets you ANY MACHINE from you grave. Adding back Pegasus for more combos next turn or Jizukiru to make your opponent worry about losing their boss monster if they can't win that turn. Trains is a mind game that makes your opponent overthink.
- When your opponent over extends, Nibiru them. A nicely timed Nib can stop a lot of decks. Unfortunately, Nib stops some combos, mainly with Bullet Train, but all you need to do is summon one other monster and you can Verte into Dragoon with ease.
- Angher Knuckle is there for when you can't XYZ summon to try to stall for a turn. It does have very good synergy with Bullet Train for card recursion though.
- Pentestag is there to poke through your opponent's defenses if need be.
- Phoenix and Robot Destroyer are there for backrow removal. Destroyer into Liebe into Zeus gets him 4 to 5 material depending on what effects you use, so that makes a nicely stacked Zeus for your opponent to deal with.
- Skypalace with a Derricrane attached is two pops and a 1000 burn that you can overlay Liebe onto.
- BLS is a good option for a lot of decks that do a lot of targeting or destroying like Altergeist. You also make it the correct way with at least one material being a level 7 or higher monster.
- I know it's weird to not main any hand traps, but with the Kaijus, I haven't really had a problem breaking boards.
With everything said and done, this is my current Trains deck and I usually end up in the top 4 with three other meta decks (we usually always split top 4). Nothing will ever come close to the greatness that is TRAINS OTK!!!!