Zurich: The track-diagram display

(Also known as the "train number display" or Zugnummern-Bild)

The track-diagram display shows a section of line in more detail than does the time-distance display. Each main track and each block are visible. (A block is a section of track that is electrically isolated from connecting ones and which for the interlocking plant is either occupied or unoccupied.)

As the sample screen shots below show, each block bears a three-digit number, which is displayed in orange.

When a block has been reserved for a train, the block's number is replaced by the train's number (in red for passenger trains, light blue for all others) Once the train has entered the block, the color of the train number reverses to black digits on a red or light-blue background.

Here, two passenger trains - one in each direction- are in the vicinity of the new flyover between Killwangen-Spreitenbach and Dietikon:

(Click on image for a larger
version and more details.)

If a track is out of service (as was the case during the winter of 2000-2001 beneath the new flyover, as shown above, where the inbound suburban S-Bahn track was being rebuilt), its block numbers appear in purple on the track-layout diagram.

Here, again, two passengers trains (in red) are moving in opposite directions through Zurich-Altstetten station, as is a westbound freight train (in light blue).

(Click on image for a larger
version and more details.)

Here is an eastbound non-revenue train (Dienstzug) - possibly one or more locomotives running light (Lokzug) - moving through Schlieren.

(Click on image for a larger
version and more details.)

If several blocks are reserved ahead of a train, the dispatcher knows that the signal at the entrance of the first block is green (or, more precisely, shows an appropriate "proceed" aspect) and can expect the train to continue at top permissible speed.

When just one block is reserved ahead of a train, however, the dispatcher knows the driver will see a yellow signal and brake to stop at the next signal, which the driver will expect to be red. (See page on signal indications.)

Here is how the Zurich dispatcher sees Dietikon station, the end of Limmattal classification yard, and the new flyover:

(Click on image for a larger
version and more details.)

The above screen sheet shots show only detail views of much-larger screens. In fact, the Zurich dispatcher can see the situation on whole sections of line in one glance, as in this view of the line between Killwangen and Dietikon, including the access tracks to the Limmattal classification yard:

(Click on image for a larger
version and more details.)

Further to the east along the line, here we have the fixed plant and current traffic between Schlieren and Altstetten:

(Click on image for a larger
version and more details.)

The track-diagram display also shows by how many minutes trains are late (+) or early (-). See tracking deviations.