Inglis & Hopkins Bridges

[NigelS]

I've passed under three military bridges (one Inglis & two Hopkins) crossing the Basingstoke Canal in the Aldershot / Farnborough area on numerous occasions, but hadn't realised until talking to somebody recently that both types are of WWI design (I'd always thought they were much later), and were heavily used then and until WW2 when the Bailey design became preferred - . The 'Inglis' type, pictured below, which is used to carry pipes, is believed to be one of only two that survives (further details of the other, which is still in use as a road bridge, and the history of the design (and the designer) can be found Here. The concept, which if scaled down would have made a good kid's construction kit, although apparently very effective and capable of fairly rapid deployment, must have been quite novel in its day.

NigelS

[NigelS]

Some further details of the 'Inglis':

[NigelS]

To finish off, pictures of the two, more conventional in design,'Hopkins' Bridges:

[Piorun]

That Inglis bridge would make a great toy! It really is designed for the field. Thanks for the pics. Antony

[Howard Chamberlain]

After reading about the Inglis and Hopkins bridges I am wondering if anyone can through some light on this bridge. It is in a reserve at Hunterville about 60 minutes drive from Palmerston North in New Zealand. It has the arrow of the MoD on many of the parts but does not seem to be either a Hopkins or Inglis Bridge. It seems more a modification of one or the other. Can anyone help please.

Howard Chamberlain

Hon Curator

RNZE Corps Memorial Museum

Linton Camp

[NigelS]

Howard

It looks as if it might be a variant of the Inglis bridge. It lacks the horizontal beams and diagonal tie-rods at the top of that at Monmouth (link in first post) but has additional supporting 'legs' which appear to be of a smaller gauge tube connected by additional clamps to the tubing of the standard Inglis components. If it is based on Inglis components it might be an official variant (ie components from the standard kit of parts), or possibly a modification introduced to suit the requirements of that particular site. It would be interesting to see how the tube 'socket' housings compare with those at Aldershot.

The surviving road version at Monmouth has been in the news (unfortunately not good) recently: Click & Click

NigelS

[Howard Chamberlain]

Hello Nigel,

Thank you for your reply. I have added another picture which may give you some more valid info.

Hello again,

One other item showing some detail of lower members.

Regards

Howard

[NigelS]

Hello Howard

Thanks for the additional photos; It certainly looks as if it is a later variant of the Inglis; have a look at these three patent documents in Inglis's (& others) name: Click & Click & Click

As far as I can see all the components (or variations thereof) used in the 'Simpsons' bridge are shown across the three documents. The systems in its later form looks very flexible and capable of expansion far beyond that possible with the original type, but would, I would think, have taken far longer to assemble from scratch than the later Bailey modular types.

NigelS

[Howard Chamberlain]

Hello Nigel,

Many thanks for this further information. I have printed it off and will give it to a couple of retd RNZE Lt Cols to pore over. The Corps may get a refurbish job and it came to me as curator of the RNZE corps Museum to search out background material. Unfortunately a lot of of old RE books and manuals were rubbished and rather shamefully tossed out. This little effort shows the value of keeping resource material.

Thank you again kind sir.

Regards

Howard

[NigelS]

A pleasure Howard.

If anyone should be interested, here are some more links for Inglis bridge patents which allow the development of the concept from the Great War onwards to be followed in chronological order (note the dates are when patents were granted, not when applied for; there may be some repeats and, for completeness, I've also included those (***) given earlier)

1917 GB 104307 - Improvements in or relating to Military Bridges and the like.
1918 GB 112184 - Improvements in or relating to Joints and Joint-boxes for Tubular-members of Military Bridges and the like.
1933 GB 395701 - A device for damping the oscillations of bridges and the like structures
1940 GB 540945 - Improvements relating to triangulated frameworks and their application to the
1941 GB 540965 - Improved junction-box for use in connection with triangulated frameworks ***
1941 GB 541475 - Improved crane suitable for erecting and launching bridges and similar girder constructions
1942 CA 403867 - Bridge Construction ***
1942 GB 548439 - Improvements relating to triangulated frameworks and their application to the construction of bridges and the like ***
1943 US 2329906 - Triangulated framework
1944 GB 561626 - Improved bridge trestle, abutment, landing stage, pedestal or like framework

Revised Patent list 14th March '15

GB1917104307 (A) - Improvements in or relating to Military Bridges and the like.
GB191422079 (A) - Improvements in or relating to Military Bridges and the like.
US1181013 (A) - Military Bridge and the Like.
US1231365 (A) - Jointing Device for the Members of Military Bridges and the Like
CA181046 (A) - Military Bridge
CA181047 (A) - Military Bridge
GB112184 (A) - Improvements in or relating to Joints and Joint-boxes for Tubular-members of Military Bridges and the like.
GB395701 (A) - A device for damping the oscillations of bridges and the like structures
GB540945 (A) - Improvements relating to triangulated frameworks and their application to the construction of military bridges and the like
GB540965 (A) - Improved junction-box for use in connection with triangulated frameworks ***
US2329906 (A) - Triangulated framework
GB541475 (A) - Improved crane suitable for erecting and launching bridges and similar girder constructions
GB548439 (A) - Improvements relating to triangulated frameworks and their application to the construction of bridges and the like ***
CA403867 (A) - Bridge Construction ***
GB561626 (A) - Improved bridge trestle, abutment, landing stage, pedestal or like framework

Something that came to light while looking through the patents is that some of them are, as well as Inglis, in the names of 'Kryn and Lahy' which must be the 'KL' monogram which can be made out in the detail of the socket housing in the first post. Apparently the Steelfounders & metalworking company was set up in Letchworth c. 1914/15 by three Great War refugees from Belgium: Jacque Kryn, a diamond merchant, his brother, George, and a colleague, Raoul Lahy. The company employed mainly Belgium refugees of which there were some 3,000 living nearby with the area becoming known as 'Little Belgium' (see Belgians in Letchworth & Help sought for commemorative Belgian plaque in Letchworth park; More information on Belgium refugees can also be found here: Belgians in Britain during the First World War and under 'Richmond Ice Rink' Here and Here )

NigelS

[Terry_Reeves]

There were two types of Inglis bridge. The Inglis Portable Military Bridge - Light Type was designed in 1913 by Charles Inglis whilst he was a lecturer at Cambridge University. On the outbreak of war he was accepted for a commission in the Royal Engineers.

The Light Type was dry bridge principally intended as a footbridge with a central gangway supported by transoms within the triangular structure. This "W" type of structure was developed by Captain Warren of the RE in the late 19th century and the inclined (triangular) design was adopted by Inglis. . The tubes were eight feet long and manufactured at the Round Oak steelworks, Brierley Hill in the West Midlands which was owned by the Earl of Dudley. The works were demolished some years ago to make way for the Merry Hill shopping centre. The bridge could carry infantry in single file over gaps up to up to 96 feet in length. An initial order of ten sets of an 88 foot span were placed by GHQ in France.

.The success of the bridge resulted in in a request for a similar type of bridge to carry first  line transport of loads up to 7 tons over a 96 foot gap. Inglis modified his Light Type design using 12 foot tubes which was called the Heavy Type and an order for 17 of the bridges was placed, the first being received in France in early 1916.  Because of the triangular shape of the structure it was found generally unsuitable for transport. This lead to Inglis designing the Inglis Bridge Mark 1 which was rectangular in cross section and had pierced RSJ's for overhead bracing whilst still retaining the tubular construction of the original bridge. Towards the end of the war a sturdier Mk 2 bridge was under design was underway at the Christchurch Experimental Establishment near Bournemouth capable of carrying the 35 ton Mark V** tank.

The Hopkins Bridge was also a Warren Truss type structure,still in use today. In 1917, hopes for a general advance by the BEF were high and a support bridge that could take traffic up to 120ft in length was identified as a staff requirement. . This design was produced by Captain Hopkins RE, formerly a bridge engineer with the Great Western Railway. The bridge , whilst much cheaper to produce than the Inglis type, took longer to construct and in the latter stages of the war the Inglis bridge was used to speed the advance and then dismantled to catch up with the forward troops, the Hopkins bridge being used as the support bridge.

With regard to Howard's bridge, It certainly appears to be made of Inglis components. I would say that a local engineer has has re-designed it slightly to suit its use which is what engineering is all about - ingenuity! Nigel - I was stationed in Farnborough the mid-1970's and became aware of the bridges you have illustrated whilst supervising Royal Engineer recruits repairing the banks of the Basingstoke canal - hence my interest. Thanks for posting the photographs of the bridges as it raises the awareness of of the importance of military engineering in WW1 which was a crucial component on all sides.

TR

Edited 21 March , 2022 by Terry_Reeves

[NigelS]

I've already mentioned an update to a 'Think Defence' article ('The Inglis Bridges') in the 'Inglis Bridge' thread, but am including a link to it here for completeness:

https://www.thinkdefence.co.uk/2023/08/the-inglis-bridges/

NigelS