Railroad
Basics
Railroad systems allow your Whiskers the opportunity to travel much faster than their little feet can carry them, even over a Stone Path. This is vitally important as your Whisker colony grows into a Whisker nation. Resources and farmland will require them to travel further and building railroads can help them reach those locations faster.
All you need are a few Rail Segments and two Rail Stations to get started. Slap a cart down and watch your Whiskers ride to their destination.
Placement
Placing rail is much like placing any pathways. You can lay down multiple segments in a straight line and will have to pay additional costs for any needed support Logs.
Where things get a little bit different are that you cannot create intersections (no T-shaped railroads), and you can create sloped tracks by raising or lowering elevation while trying to place a long track.
You may place any number of Rail Stations on your tracks, but you need a minimum of two for your Whiskers to even consider using your railroad system. They have to have somewhere to go, right?
Only one train cart (carrying 12 Whiskers maximum) will run on any given rail system and will operate automatically. The cart will wait a few moments at each Rail Station before moving onto the next. If you add too many stops, your Whiskers may have to wait a long time for the next cart to arrive.
Physics and Steam
Railroad systems are subject to some level of in-game physics such as friction on the track. If you are building small railroad systems or ones with frequent stops, you may never notice that your carts are slowing down between stops. Each time a cart stops at a Rail Station, it gets a little boost of speed when it gets on its way again.
If you are planning to use railroad systems to cross large distances (50+ segments), you will need to plan accordingly. This is where steam may come in handy. The Rail Booster allows you to apply a significant single-direction speed boost to your passing carts, both fixing the friction problem and decreasing transit time.
You may use more than one Rail Booster on a line (remember to duplicate for the return trip or between each station) to achieve increased speeds. There are diminishing returns on speed enhancement, so your dreams of sending a Whisker to the moon won't be happening.
Cost
Before you start building railroads, it is important to take note of their significant cost. At 1 Iron Bar and 1 Plank for each Rail Segment, the cost can be extraordinarily high when first unlocked. Make sure you build a sufficient supply of resources before you get started.
Don't forget to calculate in the cost of Rail Stations and Rail Boosters (and the necessary Steam Pipes). All of these cost Iron Bars too!
Support costs can also become a concern. Crossing waterways with rail can get extremely resource-intensive. Remember to check out the Masonry tab as Stone Archways can help reduce the cost of Logs at the price of Cut Stone.
Congestion
Whiskers are happy to queue up at a Rail Station if they think it is their fastest route to a location. Since a cart can only hold 12 Whiskers, this can lead to long lines of idle Whiskers if you are not careful.
For the most part, Whiskers will choose the nearest Rail Station that gets them to their destination. If the train station is full and there is another train station nearby, they will queue up at the nearby station. Whiskers may navigate to the first station before realizing the congestion and picking the alternative option. Keep this in mind when trying to solve congestion issues.
You can also consider speeding up the rail line with Rail Boosters to reduce wait times or limiting the reasons Whiskers need to use a particular line (e.g., fewer job assignments on the other side).
