How to signal a route

After bugging various people on various occasions with various subsets of the stuff below, I brought it all in one place, hopefully.

Basically, you need an idea of (1) how it is done in the prototype, (2) how RW treats signalling, and (3) where the major pitfalls are.

High level

Blocks should be of similar size. Calculate the maximum occupation time and communicate it to scenario authors. This is calculated as the distance from the signal at the start to the furthest remote link (the ones with the number on the arrow) of the signal at the end plus the maximum train length, all that divided by the usual travel speed in this block. Minimal intervals for scheduled trains should be a few minutes more than this figure, at least.

At portals, extend the branch by a few miles of plain track and place proper block signals (about two per direction). This will greatly help scenario authors debug their scenarios in case of congestions.

Make the speed limit which is set as a track property (and in the track rule) somewhat consistent with the signal distance. See here (and Mark's pointer to his handy measuring tool a few posts down) for more on the topic.

Don't worry too much about the finer details, just try a full brake application (not emergency brake) at maximum speed in a few places with a selection of trains and note the braking distance. Then add some 30% or 50% and people will love you. The important thing is fundamental awareness of the issue to avoid player frustration.

Be sure to have some space between the signal and the next switch. Rules vary widely (two quick figures: 6m - 200m), but basically, the signal is meant to keep trains from running into switches which are not set for them and/or collide with trains there, and this means that the train must safely halt before such points, and safety margin is a good thing to have. At the same time, many station layouts simply don't allow for big margins, compromise like they do in the prototype. And remember that the length of the safety margin should fit the speed of the train, in principle.

Medium level

The track network must be spanned by complete networks of signals for each possible direction of travel. This means that every remote link (with a number on the arrow) must point to a link 0 of another signal without a switch in between. For single link signals, the unnumbered link 0 must point to the next link 0, again without a switch in between.

There should be no occasion to drop off wagons within the links of a junction signal, i.e., don't place your remote links deliberately far.

With the default signals, you must keep the shunting in "yard areas". These are reached via "yard links" and left via dedicated "yard exit" signals. Yard links are the last links of signals having 1E or 2E in the name (and you guessed it: 1E signals have 1 such link and 2E signals have 2).

Be sure to have each and every track in every station marked, be it platform, siding, destination. Also those that you find irrelevant, other may not. Granted, there are scenario-based markers, but how are you going to communicate about the trackwork without a reference name.

I also suggest placing a destination marker on each route track near the station, it may help the scenario author to make his orders very clear if the dispatcher needs it.

Low level

Be sure to have the remote links beyond the curved part of any switch. Look at the ribbon frame, not the blades. The logical "node" of the switch in the abstract track network is where the curved ribbon meets the straight track pieces.

Be sure to have the remote links before any further signal. They need to send information in the direction of the arc, so if link 0 of the next signal is behind them, you cannot expext things to work.

Any AWS & TPWS goes before link 0, i.e., on the side of the arriving train. The arrow of these objects must point to link 0 of the signal to which they refer.

Be sure to pick the right signal. Refer to Mark Brinton's guides and/or the Wiki for details, they do not fit in any blog post. As a general rule, link 0 goes next the signal post, link 1 goes beyond the switches in the "most important" track, link 2 and following go to lesser tracks. If you have 4 tracks beyond a junction, you need a signal with 4T in the name.

When you place a signal shape, you need to rotate it by dragging the mouse to the side until the orientation roughly fits. If you get this wrong, just delete the signal. You can rotate it and then click on the links hoping for them to switch directions, but it is safer to redo this one signal.

References

Mark Brinton's guide, part 1 and part 2

The RW Wiki (unfortunately still lacking the illustrations as of this writing):
Signal Asset Glossary
Setting Up and Using Signals