The problem facing Sentinel 7109's chimneys was that the original cast base units were well past their best and that to use them would have only led to a long outage soon after becoming steam-worthy again.
A pattern had to be made to make the mould for the castings. It was made in four parts (with possibly a fifth but I've never been able to figure out where it could fit!).
|Front (1) Outside Profile|
|Front (2) Inside Profile|
|Rear (3) Outside Profile|
|Rear (4) Inside Profile|
Six castings were eventually requested: a prototype for Sentinel 6515 'Isebrook' at Quainton Road; one each for the Sentinels at the Middleton Railway, Elsecar Heritage Railway and the Bo'Ness and Kinneil Railway and finally two for 7109.
This is the prototype used to check that the pattern was correct.
|Prototype casting before machining|
|Prototype after machining|
|New and old comparison (1)|
|New and old comparison (2)|
7109's castings arrived in the middle of April 2014.
|Nice new pair|
Again, all the pipework and blast nozzles have to be carefully made to fit together. Hence, the whole job has been passed to MSR as it is beyond the capabilities of equipment available at Midsomer Norton.
Prototype and pattern pictures were kindly supplied by Richard Nixon.