Improve wording on signals in Rail Signals Basics tutorial

[Hornwitser]

After some discussion on the confusing workings of the yellow signal on the Technical Factorio discord it was pointed out that the Rail Signals Basics tutorial has this to say about the signal colours:

signal-tutorial.png (41.31 KiB) Viewed 1121 times

The problem with this description is that a signal into a block that is reserved by a automatic train and thus soon to be occupied will be either red or yellow depending on whether the train that reserved the block will go through that signal or not. For example:

reserved-block.png (921.94 KiB) Viewed 1121 times

Train is going through signal on the right and it's yellow. The block is not occupied yet, but the signal on the left is red.

It's also unclear if the pass in "Train may (not) pass" refers to the block ahead or the signal itself. Either way the notion that "Train may not pass" on a yellow signal is wrong, automatic trains reserve the blocks ahead of them that their stopping point is going through and in doing so makes it so that they always pass signals while they are yellow.

For these reasons I suggest the wording be changed. Maybe something like

Red: The block ahead is occupied or will soon be occupied. Trains may not pass the signal.
Yellow: The block ahead will soon be occupied by an incoming train. A train is about to pass the signal.
Green: The block ahead is available. Trains may pass the signal.

[NotRexButCaesar]

+1 The false information on the yellow signal I would even consider a bug.

[SoShootMe]

For these reasons I suggest the wording be changed. Maybe something like

Red: The block ahead is occupied or will soon be occupied. Trains may not pass the signal.
Yellow: The block ahead will soon be occupied by an incoming train. A train is about to pass the signal.
Green: The block ahead is available. Trains may pass the signal.

I agree on the ambiguity of "Trains may (not) pass" and the inaccuracy for a yellow signal in the current wording, but I think it is troublesome for another reason, even in your suggestion. The context isn't explicitly established in the tutorial (perhaps another simple improvement) but taking it to be only about automatic trains then, as you noted, they never pass green signals so "Trains may pass the signal" doesn't actually make sense.

The tutorial begins by showing locomotives colliding when there are no signals, and states that trains see the signals rather than other trains. I think this means a simple expansion on what red and green mean allows the action of automated trains to be readily inferred, and also serves as guidance when manually controlling a train on a network with some automated trains:

Red: The block ahead is occupied or will soon be occupied. It is not safe to pass the signal.
Yellow: The block ahead will soon be occupied by an incoming train. A train is about to pass the signal.
Green: The block ahead is available. It is safe to pass the signal.