C# .NET and WPF (Windows Presentation Foundation)
are used to develop the track designer. WPF is used since it's
a very rich platform and provides very rich graphic features.
Moreover, WPF controls are inherently extensible by
allowing for wide-spread customization of their appearance
that adapts to the performance requirements [5]. Fig. 2 shows
the screenshot of the track designer.
The designed track is saved in XAML (Extensible
Application Markup Language) format. XAML excels in
three key areas: expressivity, comprehensiveness, and
extensibility of user interfaces [6]. Since XAML is not
compiled, the user can edit it at anytime and quickly load it
at runtime.
Once the designing of the track layout is finished, the
XAML file is loaded in the DCV which is running in the
client tier. Fig. 3 shows DCV with the track layout loaded.
As mentioned earlier, this is the HMI (Human Machine
Interface) that is exclusively used by train dispatchers for
monitoring and controlling the train traffic in the
Metropolitan unit. The HMI is a vital component of any
SCADA system because it provides the interface to monitor
and control the entire system. A SCADA system's accuracy
and the stability depend mainly on the HMI. Moreover, all
the GUIs (Graphical User Interfaces) are designed based on
the guidelines on how to create a robust and an efficient user
interface. The dispatchers are highly skilled users and the
proposed GUI design is focused on giving them optimal
support rather than being easy to learn [1].