GWR Route: Banbury to Wolverhampton

Solihull Station: gwrs1566

Measuring the deflection of the new plate girder bridges over Blossomfield Road just south of Solihull Station, as King Edward VII and other locomotives pass overhead. This roadway had been widened from 25.5 feet to 42 feet at the local council’s request for which they contributed £1,118 to the work. The following extracts from the Railway Clauses Consolidation Act (1845) and the Board of Trade Regulations for railways apply to railway bridge design and explain some of the features that can be seen:

1. A turnpike road bridge must be at least 35 ft wide in the clear between abutments and must have a clear headway of 16 ft in height for a minimum width of 12 ft.
2. A public carriage road bridge must be 25 ft wide in the clear with a headway of 15 ft for a minimum width of 10 ft.
3. A private or occupation road bridge must be 12 ft wide in the clear with a headway of 14 ft for a minimum width of 9 ft.
4. In skew bridges the dimensions for width must be measured on the square or at right angles to the direction of the road.
5. Bridges carried over the railway must have the same width in the clear measured on the square between the parapets, as bridges under the railway must have between the abutments.

A railway company need not construct public road bridges, either over or under the line, of greater width than that of the road within 50 yds of the point of crossing, but in no case shall the bridge be narrower than 20 ft. If advantage is taken of this provision and a bridge constructed of less than the proper width for the particular class of road, the railway company must widen it to the proper width, if at any time subsequent to the construction of the bridge the road be widened. ·

In order to carry a road over or under a railway the road has sometimes to be raised or depressed. The gradient of the altered road need not be better than the average gradient within 250 yds of the point of crossing, but if the existing gradient within 250 yds of the point of crossing are better than the gradient of the altered road, then the latter must not be steeper than the following:

• Turnpike roads ... ... 1 in 30
• Pubic carriage roads ... ... 1 in 20
• Private or occupation roads ... 1 in 16

1. In cases of bridges carrying roads over a railway, there must be a sufficient parapet on each side of the bridge not less than 4 ft high and fences on each side of the immediate approaches to the bridge not less than 3 ft high.
2. All bridges under a railway should be provided with handrails or parapets, not less than 4 ft 6 in above rail level.
3. In a wrought iron or steel bridge the greatest load which can be brought upon it, added to the weight of the superstructure should not produce a greater strain on any part of the material than 5 tons per sq inch where wrought iron is used, or 6.5 tons per sq inch where steel is employed.
4. The heaviest engine, boiler truck or travelling crane in use on railways afford a measure of the greatest moving load to which a bridge can be subjected. These rules apply equally to the main and transverse girders.

Robert Ferris

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