Other countries, particularly the United States, had started introducing diesel locomotives in large number from the 1930s onwards. All the pre-grouping companies experimented with them, but none produced them in large numbers. The
LMS made the largest strides by starting a successful series of diesel shunting locomotives, the successors of which are still in service as the
Class 08. The LMS also experimented with mainline locomotives, with their
10000 and 10001 type being the first to enter mainline service in the country. ==Early BR diesel locomotives==