Odd coach

[chunky hump]

After a recent trip to Belguim and Holland, travelling on various trains, I noticed that there is always one blue and yellow Dutch liveried coach on the international trains between Brussells and Amsterdam where as the others are the new livery, does anyone know why this is?

 

[Schnellzug]

As they're as hoc formations until and if those new Fyra things do finally come into service, perhaps NS are having to put in whatever coaches they can to make up the required formation?