Cast iron bridge beams were in vogue for no more than 20 years.
Wrought iron would soon take over.
'Brunel used wrought iron for the tie bars that hold these bridges together and has gone on record as being unhappy with the use of cast iron for bridge beams, ' said James Sutherland, former partner of consultant Harris & Sutherland and advisor to English Heritage. 'It would be another five years or so before wrought iron technology was sufficiently developed'.
After the collapse of Stevenson's cast iron Dee Bridge in 1847 and the successful completion of the wrought iron Britannia and Conway rail bridges in 1850, the more certain tensile capability and relative ductile behaviour of wrought iron spelt the end of the line for cast iron bridge beams.