In this part we build the first junction (in #openttdcoop we always call it "hub"). Since we always build multi-track-junctions, a junction is a bit more complicated than it seems on the first look. Since we want to build efficient and fast railways we need efficient and fast junctions as well. For the start we will analyse a so-called "Side Line Hub" (or "SLH" for short).

We find several important things here:

• A mainline (also known as "Axis" goes from south to north (you can find it quite easy, mainlines have at least two tracks in each direction). The sidelinehub has to connect a sideline to a mainline. This is the simplest case of a hub in our games. It is usually called "T-Hub" (just lean your head right and you will notice why).
• I know what you are thinking: "Why are they doing this weird things?". The answer is: because it easy the simplest thing in the end. Just imagine a game with 300+ trains and 100+ stations and every station has its own connection to a mainline with high traffic. All this entering/leaving trains will slow down other trains - it's some kind of chain reaction. Hubs are intended to be fast connection points from sidelines to mainlines. Traffic from stations are bundled to sidelines and via a Sideline Hub they are bundled to a massive mainline. This ensures a fast and comprehensive network since we have fast connections between sidelines and mainlines.
• Every hub has a name! Not only because we are gifted writers but also because of finding all these hubs in the future. On a typical 512x512 map we end up with at least five "Backbone Hubs" (explained later on) and at least 12 or even more Sideline Hubs. Since #openttdcoop has something to deal with both communication and coordination it has proven that "Look at SLH 3" is easier to communicate rather than "Look at this hub east to the hub which is west of the eastern one". This ought to be obvious.
• Close signaling. Always place signals as close as possible to a track split. This prevents unnecessary red-signal-times when a train moves over a split.
• Think big! Our trains have a length of 10 spaces. If it is too long for a byline it therefore blocks not only the byline itself but also the mainline. On a good junction the byline is long enough for one whole train to wait. The Hub on in the picture is a quite compact one - but despite of its small size it has all it needs!
• You can get from each direction to any other direction. Since we want to make our railline expandable, we don't want to rethink all the old hubs in the future. It is better to build a hub with as many features as possible right at the start rather than heaving a headache in the future.
• A clean building style. You are not at your own (and this is probably the best thing about #openttdcoop). Unfortunately, most of us can't read your mind and therefore it is best to make a clean building style everyone understands. To be more concrete: don't do unnecessary tracks, make comments (by using signs) of your ideas. Signs do not cost anything at all - except some pressed keys on your keyboard.
• Last but not least: the mainline has always the highest priority! As you see in our example, the mainline goes straight, no slope, no curve, just straight.