So I’ve been watching a few videos on YouTube where users consistently are doubling the line right along the entire length of the line. There are a couple of reason why you wouldn’t want to do this in the early game:

The cost can be prohibitively expensive and, in the early game, you need to keep construction costs down so that you can use the money to ensure your lines are as efficient as possible. The maintenance or running costs would effectively mean you’re paying double to maintain the line.

I want to introduce a new concept to these people whereby you can increase your line capacity (ie run more trains, more frequently) without having the extra costs associated with doubling the track along the entire length.

These are called passing loops. Please consider the following diagrams:

In Figure A, you’ve created a passing loop and you have two trains, both at either end of the line. The passing loop is signalled in such a way where it allows uni-directional travel (ie they can only go one way along the line), so that if the red train arrives at the loop first, it will wait until the green train arrives at the loop and hence clears the section.

In Figure B, you can see that now both trains have entered the protection of the signalled block in the loops. Note that in order for this to work properly, you must not place any signals anywhere else on the line outside of the loops unless you have more passing loops further up or down the line. However, you’d still only place signals within the loop, to create an area where trains can wait safely.

In Figure C, you can see that both trains have now passed each other and can proceed safely to their destination.

All arrows indicate direction of travel.

It’s important to note here that if you have two trains running on the line, you will require 1 passing loop somewhere along the middle of the line. If you have four trains running, you will require 2 passing loops at a third interval on the line. So essentially, once you have two trains running, for each additional train you’re running, you will require an additional passing loop along the line. At a ratio of 2 trains to 1 passing loop, so 8 trains will be 4 passing loops. Once the line is running effectively, and returning a healthy profit, you can then consider whether you’ve reached the capacity of the line and it is worth doubling the line and hence allow block signalling to control the number of trains along the length of both lines.

Anyways, I hope this helps you understand how passing loops work and how effective they can be at keeping costs down but maximising on capacity and hence the frequency of trains you can run along the line.

Any questions, comments or suggestions please feel free to post below.