#openttdcoop

SRNW may be nice to a certain capacity but once productions get high you’ll find that the networks become very hard to manage. In this article I’ll introduce a new type of SRNW; Selfregulating terminals fed by selfregulating subnetworks, this approach completely renders the dummy trains obsolete and makes it much easier to deal with big primary industries.

For this article I’ll assume you know what SRNW is, how it works and are familiar with the terminology. For a crash course on SRNW you might want to have a look at this wiki page
When industries serviced by SR stations get higher productions (high roughly meaning more than 1000 units a month) you’ll find that expanding the stations is a tedious and complex task resulting in monsters such as the one below.

Instead of making use of dummy trains this new approach uses a loop with trains transferring to a terminal. Each time a full train unloads at the terminal a mainline train is allowed to load at the terminal. Below you can have a look at the feeding loop.

The loop makes use of a technique that has been seen before in PAX-games. Basically you just flood a load of trains onto a loop that connects to several stations at primary industries. Trains simply want to go through the first station because this is the easiest route to their next stop. When a station is full the train is forced to continue on the loop and try again at the next station. If a train does not get through a station at all it will end up in the overflow depot, controlled by a simple timer as seen in every SRNW. When a train does make it through a station it will go to a waypoint, where a simple conditional order filters out trains that are more than 90% loaded and trains that are less than 90% loaded. Trains that are less than 90% loaded will go for another loop around the pickup stations. Those that are more than 90% loaded are considered full and are allowed to unload at the terminal. If a train enters the terminal it will allow a train waiting at the ML-side of the terminal to enter the station and pick up a load, exactly like a dummy would in a conventional SRNW setup. The kind of SRNW used for the sub-loop is highly inefficient and not suitable for the top-level network but it is fine for low throughput sub-networks and easy to set up.

Below you can see the mechanism where the feeders trigger ML trains. Basically I just stole it from the train counters. It converts a red signal of any length into a short green signal making it perfectly suitable for our purpose.

Apart from the sub-loops the rest of the SRNW is the same as any SRNW. Another pro when using this technique is that you probably have less pickup stations, making your sidelines more manegable and easier to expand into multiple lines, which you’re likely to want with the new high capacity stations.

Here you can get the savegame I took the images in this article from, it has a single working selfregulating terminal.