The first reference to 10000's designation as Class W1 was on 9 November 1926, but where the widely adopted name of  'Hush-Hush' came from is disputed. It could be that the nickname arose  in the late summer of 1928, as news of Gresley's new locomotive began to leak out, however other sources suggest this was possibly an internal  Darlington name that came from the distinctively quiet motion sound the  loco made, or even because of a mistaken caption that featured in a  Pathe© News item.

On 20 November 1929, nameplates were  drawn up featuring the name British Enterprise and were cast soon after, but these plates were never fitted and the loco remained unnamed, being referred to as 'Hush-Hush' ever since. Yarrow's had completed the  boiler in February 1929 and on April 3rd the chassis was moved from  Darlington to Glasgow for testing, these being completed by October 1929 and it was during this period that wind tunnel tests led to the unusual front-end design that gave the W1 part of its distinctive appearance.  Official photographs were released on December 10th and the first trial  run took place on December 12th, followed by another on December 29th  and, on 9 January 1930, the first trip to Kings Cross, although it was  to be a further six months of trials though before 10000 finally entered traffic on June 20, 1930.

Between June 1930 and May 29,  1933, 10000 ran 70,000 miles in service, from Kings Cross to Edinburgh,  including the Flying Scotsman and Queens of Scots services, but in 1934  modifications and a general repair took 10000 out of service for just  over a year, the locomotive returning to traffic on June 13, 1934. At  the end of January 1935, a Kylchap double blastpipe and chimney was  fitted, which eventually required the fitting of a smoke lifter for  better smoke clearance. On August 21, 1935, 10000 was returned to  Darlington for the last time in its original form, having covered  another 20,823 miles since June 1934. 10000 had proved to be extremely  capable, but it was also unreliable, as out of the 1,888 days in  service, the locomotive spent 1,105 at Darlington Works alone.

This model represents No. 10000 in its 1935 condition fitted with a double chimney.