Clan Project Study

In April 2014, the Clan Project invited the AST Group to undertake a study to assess what improvements might be made to the original Clan design, with particular emphasis on improving its power and therefore its haulage (and thus money-earning) capacity.

ASTS issued a detailed feasibility proposal to the Clan Project on 9/4/15.  The proposal covers 94 pages, has 34 charts, tables and CAD Images, and 29 specific recommendations.  The recommendations were aimed at improving performance to Britannia levels and to improve reliability.  The principal recommendations were;

  • increase boiler pressure
  • installation of a single Lempor exhaust system
  • remove stress raisers from the frames
  • fit multi-ring narrow lightweight piston valve rings including bronze ones
  • adopt direct oil injection rather than atomisation for piston valve lubrication
  • steam injection into the primary air supply to eliminate clinkering and improve grate life
  • a number of detail design changes to improve on BR Standard design features.

In carrying out the study through the use of 21st century problem solving techniques and CAD, a likely cause was found for the poor piston ring wear with BR Standards that were fitted with a single slidebar arrangement.  On these, piston rings required changing on average at 10,000 to 12,000 mile intervals and exceptionally at 5,000 to 6,000 miles.  Other BR Standard classes achieved 25,000 to 36,000 miles.  This is a problem that existed in the 1950s when they were first introduced and is still with us in the 21st Century.  A modification has been proposed to improve the slidebars supports; the same modification should also work on other classes fitted with the same slidebar arrangement such as the Duke of Gloucester, the Britannia’s and BR5’s.

Note: The “Modernizing Options”  page on this website lists part of the large repertoire of options that the AST Group has a to choose from, each one being of “tried and proven” value.