holcroft valve gear造句

• The D57 design was developed further in 1950 with the smaller cylindered Gresley-Holcroft valve gear that was used on the D57 class.
• The other change was the discontinuation of the Holcroft valve gear because of the difficulty experienced in acquiring suitable spare parts for the prototype.
• The main visual difference between the K and K1 classes was at the front end : the K1 incorporated a vertical metal cover above the front buffer beam to protect the third cylinder and associated Holcroft valve gear assembly from the elements.
• This variant therefore held an advantage over Gresley s design, as the Holcroft valve gear would be immune to variations in valve events brought about by heat expansion of the valve spindles and flexing of the conjugation levers when in heavy use.