The present massive bridge has two predecessors. Since 1851, a wooden swing bridge, known as the Unterspree Bridge, stood about 70 meters upstream. It was built to carry the connecting railway between the Hamburger Bahnhof and the Potsdamer Bahnhof over the Spree. Because the wooden structure quickly became dilapidated, the railway directorate had the first wrought iron three-hinged arch truss bridge in Germany built south of it in 1864–1865.[2] It served the connecting railway and, from 1871, also road traffic, and soon after its opening it showed deformations because the pillars were insufficiently founded. The problem worsened with the expansion of the railway tracks.[3] The bridge had been owned by the city of Berlin since 1876, which had frequent repairs carried out, but the static problem could not be eliminated in this way. After the connecting railway had largely lost its importance, the Moltke Bridge was closed in 1884 and its demolition was decided as part of the canalization of the Spree. The demolition took place between February and September 1887, partly by blasting and partly by manually demolishing the massive pillars. The blasting was carried out by the Railway Pioneer Regiment.[4]
The new bridge was now to be made of stone and be the width of the approaching Moltkestrasse (26 m). – At the start of the demolition work on the iron structure, a wooden emergency bridge had to secure road traffic across the Spree, which was able to go into operation in 1886.[2]
The actual work on the Moltke Bridge began with a new pillar foundation in 1886 by the Philipp Holzmann company and lasted until the summer of 1888. In the summer of 1889, a document box was walled into one of the new pillars. The planning and awarding of the contract for the bridge superstructure were delayed because negotiations were taking place between the Prussian state and the city of Berlin about regulating the Spree, which resulted in a change in height compared to the previous bridge. The tender for the sandstone work was won by master stonemason O. Plöger, who was able to supply the required amount of material at a reasonable price. The material was weather-resistant red Main sandstone.