Prussian industrialists, observing the construction of the Austrian railway line from Vienna to Kraków, were afraid of the competition so they began promoting the project of the Upper Silesian Railway (Oberschlesische Eisenbahn). The route was to run from Wrocław on the left bank of the Odra through Oława, Brzeg and Opole, continuing through Gliwice towards Upper Silesia, and in the opposite direction – as far as Berlin. The construction was completed in 1844 – 1847 by the Lower Silesian-Markish Railway Company. The main railway line was supplemented by the following connections built under local initiatives: from Wrocław to Jaworzyna Śląska (1843), from Jankowa Żagańska through Żagań and Niegosławice to Głogów (1846), from Brzeg to Nysa (1847 – 1848), from Legnica to Jaworzyna Śląska (1856) and from Wrocław to Leszno (1856).
Soon, in Prussia major railway lines were built from Berlin to Szczecin (1843), Poznań (1848), Gdańsk (1851 – 1852) and a line to Königsberg (1857) through Krzyż and Bydgoszcz with a monumental bridge over the Vistula in Tczew. In 1856 a connection was built between Poznań and Wrocław, and in 1862 – between Bydgoszcz and Toruń.
In 1849 – 1851 stagnation could be observed in the construction of the lines in Silesia, caused by the Spring of Nations and the financial problems of investors. With time, the first and the largest railway company in Prussia – the Upper Silesian Railway Company (TKG) – became the owner and operator of a 988-mile (1,590 km) long network. At the peak period it employed more than 17,500 workers. TKG built numerous railway lines in Upper Silesia and in the Grand Duchy of Posen (Poznań): Katowice Ligota – Murcki (1852), Chebzie – Tarnowskie Góry (1859), Szopienice – Sosnowiec (1857), Mysłowice – Bieruń (1859), Bieruń – Oświęcim (1863), Poznań – Drawski Młyn (1848), Poznań – Leszno (1857), Poznań – Toruń with branches to Inowrocław and Byd-goszcz (1872-73) and Inowrocław - Mątwy (1882). Local railways connected to the main lines were established on a mass scale.
Apart from the Upper Silesian Railway Company there were also smaller companies which successfully operated in the dynamically developing railway transport market:
• The William Railway Company built the Nędza – Rydułtowy – Rybnik – Orzesze – Mikołów – Ligota Pszczyńska line (1855 – 1858).
• The Right Bank of the Odra Railway Company put the Opole – Tarnowskie Góry (1858), Tarnowskie Góry – Bytom – Siemianowice – Szopienice – Murcki (1859 – 1868) and Kluczbork – Lubliniec – Tarnowskie Góry (1883 – 1884) lines into operation.
• The Markish-Posen Railway Company put into service the Frankfurt – Zbąszyń – Poznań connection (1870).
• The Wrocław-Warsaw Railway Company commissioned a line from Oleśnica through Kępno to Podzamcze (1871 – 1872).
Private companies also financed the Oleśnica – Krotoszyn – Gniezno (1875) and Poznań – Kluczbork (1876) lines. On the other hand, the connections Poznań – Września (1887), Gniezno – Nakło and Września – Strzałkowo (1888) and Mątwy – Kruszwica (1889) were established as state enterprises.
Generally, in the territory of Prussia railway lines diverged from Berlin in various directions. Subsequent ones were built as branching lines leading to industrial centres and larger cities, while local connections were built in between. In addition, industrial narrow-gauge railways were put into service. Their gauge was mainly 785 mm and they had an extensive network of sidings.
In 1850 the steelworks in Upper Silesia satisfied half of the steel requirement of Prussia, and zinc mills in 1860 were the largest producers of this metal in the world. The needs of Silesian industry and the large population in that region were conducive to the construction of a dense railway network, mainly as a result of the efforts of local railway companies. Therefore, as early as 1854 the Upper Silesian Railway Company undertook the construction of the main railway connections from Tarnowskie Góry through Chebzie to Wirek and from Karb through Rozbark to the Kunegunda zinc mill.
A thriving industrial centre was also situated in the Sudeten Foreland, with coal mines in the region of Wałbrzych and Nowa Ruda. Railway provided options for the mass export of goods and raw materials. In 1843 the Wrocław-Świdnica-Świebodzice Railway Company completed the construction of the line to Wrocław where a large river port on the Odra was in operation, and in the following year a branch line was built from Jaworzyna Śląska to Świdnica. Previously, relevant permits were obtained from the Ministry of War since at that time Świdnica had the status of a fortress.
An undertaking that was interesting from an engineer's point of view was the state-financed construction of the Silesian Mountain Railway. The purpose of the line was to enable the development of the manufacturing centres of the textile and mining industry in the area of Lubań, Jelenia Góra, Kamienna Góra and Nowa Ruda. It was commissioned section by section: Zgorzelec – Rybnica with a Lubań – Węgliniec (1865), Rybnica – Jelenia Góra (1866) and Jelenia Góra – Wałbrzych (1867) branch. Two tunnels were bored on the latter section.
One year later the Silesian Mountain Railway was connected with the Wrocław-Świebodzice Railway via the station Wałbrzych Miasto (Wałbrzych City). In 1869 the lines were transferred to the administration of the Royal Directorate of the Silesian-Markish Railway, and in 1873 they inaugurated the connection with railways of the Austrian company StEG – the Wałbrzych – Boguszów Gorce – Mieroszów – Mezimesti line.
The railway network in the territory of Poland under Prussian rule attained its near final shape around 1880. At that time, the authorities introduced facilities such as new regulations governing the construction and operation of secondary railways, that is, lines that could reach a speed of up to 19 mph (30 km/h). Restrictions were applied to requirements concerning signals, grade-crossing gates, fencing of tracks and route supervision, and the construction of railway subgrade. Despite this fact, the profitability of building new connections decreased, entailing reduced interest among investors and thus the construction of subsequent railway connections was taken over by the state, which also started acquiring the existing lines from private owners. At that time the connections: Szczecin – Goleniów – Gryfice – Kołobrzeg (1882), Toruń – Grudziądz – Malbork (1883), Olsztyn – Szczytno – Ełk (1885), Olsztyn – Braniewo (1885), Zbąszyń – Międzyrzecz (1885), Zbąszyń – Wolsztyn (1887) and Fordon – Chełmża (1893), with the then largest bridge over the Vistula, were put into service.
In 1876, Prussia had 50 railway company boards administering 63 separate networks with nearly 1,400 transport tariffs. This was too much for the pragmatic Germans. In 1884 the Royal Railway Directorate was established in Wrocław whose task was to put the whole system in order. The directorate assumed control over all state railways.
In 1892 an act on railways and private commuter railways was passed. This act provided the basis for the construction of local narrow-gauge lines (e.g. in Środa, Żnin, Ełk, and Wrocław) and short-distance local connections.