Footplate: Two different widths
Plain or fluted
Cab: The cabsides
of the first sixty engines had a large sweeping cut-out whereas the later
engines had a standard two arc opening. With the fitting of Belpaire fireboxes
the cabs were raised to allow the spectacle windows to be refitted and there
were two distinct cab roof profiles. Cab roofs were latterly of steel replacing
the earlier canvas covered wood.
early smokeboxes had a plain front with ringed door. Later snap head rivets were
used and from c.1920 the smokeboxes had a pressed front with Churchward type
door without the ring.
As well as a round top firebox wrapper,
two different B4
firebox wrappers are provided with alternative positions of the washout plugs.
Steps: The front
step and upper rear step were different on the first sixty engines.
Reversing rod: The first sixty had a straight rod; the remainder
had a curved rod.
built-up parallel type. From 1919 tapered cast iron type began to be fitted.
Top feed: From
about 1913 onwards some forty on the class carried B4 boilers with top feed.
Changed from large type with visible rivets to a smaller plain design.
ATC: A large
number of the class were fitted with ATC equipment in the 1930s.
Most have the front lamp brackets attached to the buffer beam but a few had the
outer brackets fixed to the sandboxes.
Many of the
earlier engines appear to have come out with second-hand iron frame or double-frame Armstrong tenders which were to be found on the class up to about 1912.
Later engines were paired with standard Dean 2500 gallon tenders. In later years
a significant number acquired larger Dean tenders of 3000 gallons capacity.