Here's an overview of the map, including call-outs that are helpful to learn.
Last time we went over the terrorist side on Cobblestone. Now we're back on track (choo-choo!) with a counter-terrorist guide for Train.
Train is another map that, like Cobblestone, has seen a lot of iterations throughout the years due to balance issues. The map itself consists of two train yards, an alley and a hallway. Your objective is to prevent the terrorists from blowing up one of two nuclear payloads.
Let's start with the inner bombsite. What usually happens is that the terrorists smoke off lower before they push down the ramp. This means it's a risk to stand far back and peek lower. After the smoke you won't know if they actually pushed site or not unless you have a teammate closer to the bomb train. You can however take an auto-sniper and shoot blindly into the smoke and do some serious damage. In addition, the long distances make the auto-sniper a really powerful weapon for retakes.
My favorite spot is the bomb train. If done properly you can dance around the train all day while you wait for backup. Especially if your team has a sniper nearby that keeps the enemies from pushing you. Peek over the train like this:
If you're lucky (or a sick aimer) you might pick up the first headshot. Then you can use a molotov to delay the push, fall back and call for backup. Most of the time your opponents will use flashes and smokes before they attack from upper, in which case you will know and have time to back off. Another option is to have another player holding upper.
A round where your opponents haven't bought weapons and you try to secure the round with as few casualties as possible.
Sometimes you want to let out your inner ninja and go for the unexpected heroic play. One really cool spot is behind the spools between lower and upper. Normally I'd advise against staying close to your enemies on anti-eco rounds because of the risk of providing them with a weapon and a chance to get back into the game. But on round two, if you managed to win the pistol round, you can pick up a submachine gun and go for it. The SMG kill reward of $600 can mean a great deal later on. I've lost track of how many triple kills I've made from this position on the second round.
Other times you want to show off your great communication skills. Tell your teammate to stay close on upper and get ready to peek, then you throw a flashbang just as you get next to the fuse box on the wall. The flash will pop right in the face of any terrorists standing at the bottom of the stairs. As soon as your friend hears the pop, he can go for a quick peek and hopefully score a kill.
On the next page: defending outside.