for the Hong Kong MTR, also built by Metro-Cammell, these cars having a very large profile. The test track was closed in 1980, and it is now home to the Stephenson Railway Museum. The prototype cars are very similar to the production fleet, with the exception of having Kiekert passenger doors, which were refitted to match the specification of the production fleet before entering passenger service. The prototype cars were also fitted with two different types of block coupling equipment (one at each end), allowing the two designs to be thoroughly tested. The prototypes featured small cabs and central end doors similar to London Underground stock, to allow evacuation of trains in a tunnel. In the event, the Metro tunnels were constructed with continuous sidewalks, making the end doors unnecessary. Prior to their entry into service in 1987, the two prototypes were refitted to reflect the specification of the production fleet. The small cabs remained in the series vehicles with a passenger seat beside offering a forward view. Livery The Metro fleet was initially painted in a two-tone livery of cadmium yellow and white that matched the Metro station design and the livery of the Tyne and Wear bus fleet until 1986. In 1995, a new colour scheme was introduced - solid red, green or blue with a yellow wedge at each end and yellow triangles on the doors. This scheme was modified slightly in 2005, in part to comply with safety regulations - the doors were changed to solid yellow to comply with the Disability Discrimination Act 1995. In addition to the standard colour scheme, a large number of special liveries were carried. These were often advertisements for local businesses such as Metrocar 4042 advertising the Evening Chronicle. To celebrate the Golden Jubilee of Elizabeth II in 2002, unit 4032 was temporarily decorated in a special gold livery. It was then returned to the red and yellow livery, which it carried until refurbishment. Between 2012 and 2015, 86 Metrocars were refurbished and repainted in a black and yellow livery. The refurbishment reduced the number of liveries in use. Metrocars 4033 and 4082 carried a promotional livery for Emirates, although they have since been repainted to match the other units. Unrefurbished Metrocar 4083 continued to carry an Emirates livery. Until 2017, prototype unit 4001 carried its original cadmium-and-white livery whilst 4002 carried an advertisement for the Tyne and Wear Metro