With the completion and approval of the static mainframe, the engineering effort is now concentrating on the rolling chassis. The rolling chassis combines the static mainframe and all parts associated with each axle set for each pair of coupled wheels.
The introduction of a brand new LNER class B17 steam locomotive, to the modern mainline network, is considered as a significant change by the Rail Authority. The B17 SLT must therefore comply with the statutory requirement for undertaking a full and sufficient risk assessment, to identify potential problem areas and corresponding mitigations, subject to independent assessment to ensure that safe working methods and results have been obtained.
The design is complete and formally issued into B17 Build Standard. The full design and manufacturing proposal is to be submitted to Ricardo Rail for approval. Suppliers have been identified and RFQ's will be issued after approval, followed by purchase orders issued against agreed quotations. The design definition has already been shared with Llangollen in discussions on the construction.
The B17 design definition for the rolling chassis describes each axle set in terms of material specifications and dimensions/tolerances for machining and assembly requirements. When the design submission is approved the full kit of parts must be obtained, first to enable each axle set to then be assembled in its own right. The only exception to this relates to the horn blocks and horn stays which can be fitted directly to the frames.
Stress analysis of the crank axle assembly has been identified in the initial risk assessment record log to define loads and stresses covering the full operating envelope of the engine. Much of the design has been derived from Tornado and the P2 (2007) where the help of the A1 Steam Locomotive Trust and David Elliott is acknowledged with our grateful thanks.