No, the British Rail class 444 train is not identical to the British Rail class 450 train. These trains are slightly different but made by Siemens Desiro.

The manufacturer of the British Rail Class 700s was Siemens.

The British Rail Class 153 were converted from British Rail Class 155s

The top speed of the British Rail Class 390Pendolino is limited to 125mph, but with the limiter off they have reportedly hit as high as 150-160mph, making them the fastest trains in the British Isles.

No, the British Rail Class 395s are not only the Japanese trains running in Britain.