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Setting up a perimiter defence using artillery turrets loaded from artillery wagons seems like a big job: naming dozens of stops and setting up the train schedule. But there is one simple idea which makes it really easy:

Give all the turret train stops the same name! Here's how it works:

A single track goes all around the perimiter of the base: branch lines and extensions can be added later as and when needed. Along the track are train stops, all of which are called "Defence". The train consists of a single engine with a single artillery wagon: this can hold 100 shells. The artillery wagon is unloaded into a chest, limited to 20 shells, which unloads into the artillery turret. The chest is connected to the train stop with a red wire. The train stop is enabled when artillery shells = 0.

So, the stop is only active when the chest is out of shells.

The train is programmed like this: Most of the time it sits at the Defence Depot. As soon as any Defence stop needs shells, that stop becomes active and will be visited. (The turret still has five shells to keep it going until the train arrives.) The train can reload up to five Defence stops (if needed) before returning to the base.

The loop on the track is used while laying out the track: as the stops are being placed the train will visit and load each new stop in turn, before looping back to the base. So the perimiter is gradually cleared as stops are placed. The loop is also useful for "branch lines" to extend the perimiter.

To extend the perimiter, just add more track and stops wherever needed: no reprogramming of the train or stops is needed!

There is no need for signals if there is one train and the track does not connect to the main train system. If signals are needed they should be place in pairs on both sides of the track, since the track is two way.

With my current base (around 400k science per second) the artillery range from the perimiter defence extends just beyond the pollution cloud: so there are hardly any attacks.

One train with one artillery wagon is able to service 48 identical Defence stops in my base.

Blueprint string for the stop:
Copy blueprint

Nice idea to use the Artillery train as the cargo wagon for the shells, I had not considered that.

Some notes from a recent test of the system:

• Make the artillery tran double-headed and leave out the loops
• Add a second rail line inside the perimiter: this can take a supply train (also double headed) and can be used with a manually-driven train to repair/replace defence stops using personal roboports. Note that personal robots will not go to work if you are in an automated train, only a manual train
• Repairs are generally only needed on initally building the defence and after extending artillery range (and if you go wild with manual targetting!)
• A single artillery train can easily supply over 50 defence stops
• If the perimiter extends past the pollution cloud, then all biter attacks are prevented.

Ancient history, I know, but a couple points:

• You don't need a Schedule Entry for each same-named stop; you just need two. Once the train exits one "Defense" stop, the next entry automatically switches to the next one down the line.
• Instead of "wait 10 seconds," I use "2 seconds inactivity." This might be a problem when first setting up defenses, but once the local boxes are full, a single train can easily supply dozens of artillery emplacements.

Thanks for your comment.

The point of having five entries for "Defence" is that the train can supply several defence outposts before needing to return to the depot to reload. So if several outposts run out at the same time (eg because the artillery range increased) then we don't need to retrn to the depot in between each supply drop.

With "2 seconds inactivity", if the range has increased then the train might just sit at the first defence stop until it runs out of ammunition: creating a massive amount of aggro from the biters who will probably destroy the train stop and the train!