I see what you mean by the 'wow' factor of the T5 project.
The circular hollow section (CHS) members up to 914m diameter which make up the abutment trusses (P10) are truly amazing.
Even more incredible is the Piccadilly Line Extension twin bore tunnel. At 4.5km diameter, this would surely enable T5 to be sited underground!
Tony Bunn, 15 Martins Wood, Chineham, Hants, RG24 8TR
Editor's note: Apologies.
Circular hollow section members used for the abutment trusses of the T5 Concourse A roof are up to 914mm. The diameter of the Piccadilly Line tunnels are 4.5m.