Rail3D*

 

Newport Example

An example of applying semaphore signals to a large layout.

This is a fictional layout by Alan Perryman, Alan posed the question of how to signal the layout.

First, the layout of Newport station and junctions:

Alan says: The diagram depicts the Newport station -if this had been a real layout I’d expect 3 signal boxes to be working this; one at each end of the station, and one controlling the junction to the east.

Applying the signals.

ok, Alan’s plan to use three boxes is reasonable for a layout this size, so let’s look at them in turn.

First, the West box. Here’s the west end of the station in more detail:

Signalling this is fairly straightforward:

  • Home signals (stop) on the approach lines from the west (A).
  • Starters (stop signals) on the platforms (C)(for trains going west). These would be normal size stop signals. If all platforms/lines have westbound moves then you will need signals on all lines. Some of these (eg for the eastbound platforms) might be shunt or ground signals instead of normal running signals.
  • The yard would probably not have any signals in the yard, as movements would be low speed and controlled by hand signal, but it would need one signal - probably a ground signal - controlling the exit. In R3D you would probably want to scatter some more ground signals around the yard to help manage loco movements, but they wouldn’t be there in real life and you could make them hidden signals
  • The siding north of the line would also need an exit signal, also probably a shunt or ground signal.

So it starts to look something like this:

Further refinements:

  • Shunt signals (eastbound) on the westbound departure lines (at B above): these would be used for locos shunting to the west on the departure lines and then reversing, the signals would control the shunt back into the station. These are not essential, but are likely in a layout of this size.
  • Further west: A station this size will probably have Advanced starters ie, stop signals on the westbound lines to the west of point B. These will be about a train length west of point B, thus allowing a train to be shunted west of the station inside these signals. If these signals are not provided, then a “limit of shunt” board would be needed in about the same position.
  • Routing information: The platform starters (At C, especially on the southernmost, west-bound lines) would probably have some sort of route indication, ie main arm for the primary route, subsidiary arm for crossing move such as fast to slow or vice versa, and a third arm or shunt disc for other moves, such as into the loco yard. A single shunt signal would probably suffice for the signals on the more northern lines as these would not be used westbound for normal running movements.
  • East bound routing: The home signals at A would need some sort of route indication. In the prototype at a layout like this, these might well be route indicator type signals - ie one arm with a displayed letter or number for the route - that’s tricky (but possible) in R3D, so you’ll probably have to be content with a two or three way junction here. These signals might also have subsidiary shunt or calling on arms as well.
  • East bound approach: Depending on traffic density, you might well find outer home signals to the west, west of the home signals by about a train length (And a bit more)

Distant Signals and Section signals

Obviously you are going to need distant signals, and this is where it starts to get complicated. Eastbound:

  • You need eastbound distant signals, a sufficient stopping distance (speeds are presumably low) before the home signals (or outer homes if provided). Knowing that the next station east is not far away, these are likely to be mounted on the same post as the previous stations starters - ie the hd type.
  • The outer homes are not section signals, the homes are. Thus the distants will clear if both the outer home and home signals are clear.
  • Given the proximity of the east station box, the westbound home signals (at A) will also carry the distant arms for the east box, so these will probably also be hd types. Again, assuming low speeds and complexity of layout, distants are not required for all routes, so a signal distant arm, clearing for the main route would be provided.

Westbound:

  • Similarly the distants applicable to the eastbound signals will be in the east box’s territory, so will be hd types sharing the same post as the east box’s homes signals.
  • If advanced starters are provided, they will be the section signals, if not the platform starters are the section signals.
  • The advanced starters are likely to be hd as well as they would probably carry the distant arms for the next box to the west.

import