In its 25^th issue of June 1851, the newspaper Kmetijske in rokodelske novice wrote (Agricultural and Artisanal News): “Correspondent from the Carniolan Region. Among such places that will be only put on the map by new times, is Borovnica, beyond Vrhnika, in the corner at the end of the long Ljubljana Moors. Such a railway bridge is being prepared there that has no parallel in any other railway line; it will be over 200 fathoms long, and 19, or according to the most recent information, even 31 fathoms high. A lot of work is required to prepare the foundation, because a lot of piles have to be sunken into the mostly soft base and vegetation before the stones can be laid. The construction will actually cover two bridges, one on top of the other; the stones are therefore already being cut in several places, but in a completely different size than for other structures. When this bridge is completed, Borovnica will be as closed as if it were separated from the world; and passengers will watch it from above like a bird flying by. A little further from this big bridge, preparations are ongoing for another bridge, which will not be much lower than the first one, but much shorter. So far, there are about 3,000 workers engaged in work on the entire route from Žalostna gora to Vrhnika; and there will have to be more of them if the work is to be completed soon.”

Novice newspaper followed the progress of the Viaduct construction and published in its 42^nd issue in May 1854 the following: “Correspondent from Austrian regions. In Vrhnika, 21 May. H. What does the railway say in our pages? Is the work accelerating? The main thing here is the big bridge (viaduct) in front of Borovnica; the columns of the lower section are all completed as if cast, they are so beautifully and smoothly carved out of stone. The brickwork is already rising on all of them and curving to arches, where one of them is already closed, and two are almost completed. The bricks for this bridge are, however, specially prepared, they are not of the same thickness, but look like a wedge, thinner at one end. On the lower section columns, between the arches, there are columns erected for the upper section, they are cut out of stone as the lower ones, and the arches on them will also be made of brick. In the middle between the lower and upper sections, a road for ordinary carts will be open and lead to the railway station from the other side. The other two major bridges in this side are also being diligently constructed; namely, in one, in Doli before Borovnica, some columns are already built almost up to the top and some to the middle; and the second bridge, in Blatni dol across the old road above Vrhnika, will be completed in a few weeks.”

The test drive from Ljubljana to Borovnica was made on 28 October 1856, just before the arrival of Emperor Franz Joseph. He travelled across the Viaduct during his visit to Postojna Cave. In its 247^th issue, on 22 October 1939, Jutro newspaper published on page 7 an article on the fate of the Borovnica Viaduct, and wrote, among other things: “Everything was in green, and thousands of lights were lit on the parapet walls, having a fabulous effect on the huge stack of walls in the evening.” The Emperor repeated the ride in July 1857, when he travelled to Trieste at the opening of the Southern Railway.

The construction was carried out with inhuman efforts, using rather primitive means compared to today’s options. Nevertheless, in 1856, when the first train passed it, the Viaduct was a real technical and architectural masterpiece. On 30 August 1856, an Austrian correspondent wrote in Bleiweisove novice (Bleiweis’s News): “The last arch of the 20-and-a-half-fathom high and 280-fathom long stone-block railway bridge in Borovnica – Franzdorf – which is said to have no equal in Europe – was completed on the 18^th day of this month.” This was his announcement of the completion of the Borovnica Viaduct, one of the largest railway viaducts in the then Europe.

In addition to the Borovnica Viaduct, four smaller ones were built in the immediate vicinity: the Pako Viaduct, Breg Viaduct (today: the Pako Bridge), Jelenova dolina Viaduct, and Dol Viaduct. A railway station, including an engine shed, a turntable, and other auxiliary facilities, was built on the plateau between the Borovnica Viaduct and the Jelenova dolina Viaduct. At the beginning, only a few trains ran through Borovnica, the first stop after Ljubljana, and their weight brought no significant burden to the Viaduct.