Negrelli constructed the Gschwendtobel-Brücke in Lingenau, a covered wooden bridge still in existence, and earned a reputation for taking part in the channelisation of the Alpenrhein and of the various Austrian and Swiss interests connected therewith.

In 1835, Negrelli was called to Zürich,[7] where he continued with similar activity, notably working on the Münsterbrücke (Munster Bridge) crossing the Limmat together with Ferdinand Stadler, who was responsible for the carpentry.

During a journey to England, France and Belgium he, like many other engineers, studied recent advances in railway construction and subsequently published his ideas of adapting this technology to mountainous regions in papers, receiving wide attention in the industry.

[4] In 1849, Negrelli was to travel to the then Austrian Kingdom of Lombardy–Venetia with the task to oversee work on public buildings, railways and telegraph lines, and heading a commission regulating traffic on the river Po.

[9] In 1850 he was awarded for his services and received a title of nobility with the designation Ritter von Moldelbe, chosen by himself in memory of his times working on the rivers Vltava/Moldau and Elbe.

[7] After arriving back in Vienna in 1855, Negrelli was appointed inspector general of the newly founded Imperial Royal Privileged Austrian State Railway Company until 1857.

Consisting of thirteen experts from seven countries who were to examine the plans made by Linant de Bellefonds it had to advise on the feasibility of and on the best route for a canal project.

In the final deliberations of the commission in Paris at the end of June 1856, his principal ideas of a canal without locks and a northern entry further to the west prevailed.

[16] Alois Negrelli von Moldelbe died in the morning hours of 1 October 1858 at age 59, probably from food poisoning causing bacterial infection.

[4][17][18] In his book Transportation and Communication of Egypt, Negrelli wrote in 1856 about the Suez Canal:[5] The connection of the two seas by a maritime canal, shortening the route between Europe and the rich countries of the Old World located at the Indian Ocean, not only for the development of global trade but also for the increase of cabotage (domestical shipping) for Egypt, related to the prosperity of inbound welfare to this country so blessed, is an undeniable necessity.