[Railway reconstruction Italy 1943-1946 published by Royal Engineers, 1946]
DESCRIPTIVE ACCOUNT OF RAILWAY CONSTRUCTION ACTIVITIES
Railway Construction considered in relation to the ultimate Railway system
10. - Line 219 - Pisa-Empoli-Florence.
A drawing illustrating the bridge repairs carried out on this line is included at Plate Nº. 32.
This is the main line connecting the West Coast Route, Line 50 at Pisa with the Main Inland Route, Line 65 at Florence. Leaving Pisa the line runs virtually due East following the River Arno closely, all the way to Florence. From Pisa, the line follows the South bank of the river. About 20 kilometres before reaching Florence the line crosses the river and then follows the North bank of the river into Florence. The line was double track throughout and was steam operated. Electrification was in process of installation at the outbreak of war, but was never completed.
When it began to appear possible that the delays, in the Serravalle Tunnel, Line 217/8 might be so serious as to prejudice the success of the Armies' Spring offensive, consideration was given to the possibilities of a rapid repair to this line by way of insurance. Although the reconstruction of the line made heavy inroads into a not too plentiful stock of U.C.R.B., and furthermore involved using, U.C.R.B. over spans far greater than any previously used, the work was put in hand.
Demolitions on the whole were heavy. 24 bridges out of a total of 39 bridges, of span of 7 metres or greater were demolished, including all large bridges. There were fortunately, no tunnels on the line. In the whole 79 kilometres of route of this line, every rail was demolished by cutting at the centre with explosives.
The reconstruction of the line was carried out by «A» Companies of 715 and 719 Railway Operating Battalions, U.S. Army, assisted by 182 Engineer Combat Battalion, U.S. Army, loaned by 5 Army and by 345 and 1334 Engineer Battalions, U.S. Army loaned by Peninsular Base Section, the whole being under the technical direction of 701 Railway Grand Division U.S. Army.
Reconstruction of the line commenced 1 February and the line was opened for traffic on 1 April 1945.
One of the most remarkable features of this line was the fact that four of the bridge demolitions required for their repair, spans of 104 feet in length. One of these bridges the River Arno required five such spans while the remaining three were each of single span. For reasons outlined below these spans were in the case of the Arno to be provided by use of U.C.R.B. and it was therefore decided to adopt the design for all four bridges. Thus on the only occasion that a 105 ft. U.C.R.B. span was required for use in a main line, it was used eight times in one short length of line.
By far the most interesting work on this line was the reconstruction of the bridge over the River Arno. This work was carried out by «A» Company of 715 Railway Operating Battalion, U.S. Army.
The original bridge at this point consisted of a five span brick arch viaduct. The clear span of each of the arches was 29.76 metres, the thickness of the piers was 3 metres and the bridge had an angle of skew of 42 degrees. The bridge was demolished by the enemy so that all arches were destroyed and piers and abutments cut down to about 8 ft. above river bed level.
Survey of the site showed that standard Lattice girder spans would not fit on the existing foundations. The other alternative of a new bridge on piled foundations was rejected in view of reports from the Italian State Railways that rock existed a few feet below river bed and that adequate penetration would be difficult to secure. It was therefore decided to make use of the original foundations and to span the gaps by use of three girder U.C.R.B. Deck spans.
Fortunately at the time the reconstruction was carried out, the level of the water in the river was low. The existing pier stumps were capped with reinforced concrete slabs and Light Steel Trestle piers erected thereon. In carrying out this part of the work, care was taken to keep as close to the downstream side of the pier as possible, so as to facilitate the subsequent permanent repair of the bridge by stages. The abutments were rebuilt in concrete.
The superstructure consisted of five U.C.R.B. spans each of the 3 girder deck type, and each 105 ft. long. In designing these girders, arrangements were made for the incorporation of additional sway bracing. As, if they had been built to the design specified for 3 girder spans of shorter length, they would have lacked lateral stability. Diagonal splice cover plates were used on the diagonal members for six bays at each end of each girder, and the unused holes in the top chord at the centre
Figure 83. - Line 219. River Arno Viaduct at Km. 19.64. Reconstruction was carried out by 182 Engineer Combat Bn., U.S.A., under Job Nº. 219/23 from 19 February 1945 to 20 March 1945. 5-105' three girder U.C.R.B. Deck spans were used.
Figure 84. - Line 219. River Arno Viaduct, showing framework for the reconstruction of the 5-105' span arches. Note the steel centring. Due to heavy shew of the arches, they were rebuilt as five square ended arches over the total width. This work was carried out by I.S.R. contractor after the reconstruction of Job Nº. 219/23. (Figure 83.)
Figure 85. - Line 219. Job Nº. 219/23, Arno Viaduct. Another view of the framework to reconstruct the arches. After two of the five sections had been built, the U.C.R.Bs were removed and the track carried on the two newly constructed 'arch-sections' to enable the three remaining sections to be completed.
of the span were filled with drifts. Otherwise, there were no unusual features in the design of the spans.
The bridge was launched by the low level continuous launch process described in Chapter IV, Section 8 (b). No launching nose was used. The motive power for launching was supplied by
Figure 86. - Line 219. Bridge oven River Pesa at Montelupo, Km. 27.740, showing the complete demolition of the 96' span. Reconstruction was carried out by 182 Engineer Combat Bn., U.S.A. under job No. 219/20 from 16 February 1945 to 22 March 1945.
Figure 87. - Line 219. Pesa River Bridge at Montelupo. Job No. 219/20 showing the reconstruction using a 105' three girder Deck U.C.R.B. span.
a bulldozer pushing the rear end of the girders. Erection and launching were carried out from the West end of the bridge.
As there was a considerable amount of U.C.R.B. material involved in this construction (nearly 800 ft. of equivalent 2 girder) it was of some importance that it should be recovered at the earliest possible moment for use elsewhere. The I.S.R. were therefore instructed to let a contract for a permanent repair of the arches to a reputable contractor. The firm of Ferrobeton of Rome were selected and started work at the site before the temporary bridge was completed. Owing to the heavy skew of the bridge, the design for the permanent repair of the bridge consisted of five square arch rings side by side in each span, but staggered to give the necessary angle of skew. Two of these rings were to be built alongside the U.C.R.B. spans, after which the track would be transferred to them and the U.C.R.B. recovered, then permitting construction of the remaining three arch rings. Unfortunately, in spite of great efforts on behalf of the contractor, it was not possible to recover the U.C.R.B. until after the end of hostilities.
Other works of interest on this line are shown at figures 86 & 87.
[Railway reconstruction Italy 1943-1946 published by Royal Engineers, 1946]