652 km (405 mi) of the line is electrified with 25 kV AC, 15 Hz overhead wire in two separate areas: from Ankara to Hanlı and from Çetinkaya to Divriği, and electrification of the remaining 344 km (214 mi) long gap from Hanlı to Çetinkaya is under construction.

Track geometry was constructed in anticipation for the addition of high-speed rail as the route has a top speed of 160 km/h (99 mph).

Located roughly 45 km (28 mi) south of Sivas, the tunnel was built as a more direct pass between Tecer and Kangal, along with slightly shortening the route, reducing grades and allowing for higher speeds with fewer sharp curves.

[3] Following the outbreak of World War I, Russia invaded the Ottoman Empire and further extended the railway into captured territory.

In 1916, under the orders of General Nikolai Yudenich, the Russian Army built a 2 ft 5+1⁄2 in (750 mm) narrow gauge railway from Sarıkamış to Erzurum, a distance of 173 km (107 mi).

However the Russian Empire threatened war with the Ottomans, should a railway line be built into north-east Anatolia.

During the First World War, a 127 km (79 mi) narrow gauge railway was constructed from Ankara to İzzettinköy and opened in August 1919.

[10] After the Turkish War of Independence and the establishment of the Republic of Turkey, a railway east of Ankara became the primary focus of the government.

The railway was opened to Kayseri on 29 May 1927, with a large ceremony attended by Prime Minister İsmet İnönü.

Since the Turkish government took upon no risk with the agreement, they only ended up paying the company for the amount of track already built.

Shortly after the agreement was canceled, another tender was awarded to a Turkish company, tasked with completing the railway to Sivas.

Construction progressed without a problem and on 1 February 1930, the railway opened between Kayseri and Şarkışla, 84 km (52 mi) southwest of Sivas.

[11] Since the railway carried a strategic importance for Turkey, the potential route of the line was heavily debated between 1930 and 1933.

However the Chief of Staff, Marshall Fevzi Çakmak, called for the railway to run along a more southern route following the Kangal Stream.

Following the submission of bids, the tender was awarded to a Turkish company owned by Nuri Bey, on 12 June 1933.

Signed on 29 June, this marked the first time a large railway tender was awarded to a Turkish company.

Construction was sped up and on 8 October 1938, the railway reached Erzincan, 156 km (97 mi) further east of Divriği.

Despite the difficult terrain, construction of the railway progressed smoothly, prompting the Turkish government to request that the completion date be brought forward.

The Turkish company building the railway accepted the request and the laying of track was greatly expedited.

[11] The Turkish company received great praise from the government, as it completed the agreed works 16 months ahead of schedule.

Plans to convert the entire line to standard gauge were first discussed in 1938, before the completion of the railway to Erzurum.

Conversion would first begin with a 22 km (14 mi) long extension of the standard gauge railway, from Erzurum to the village of Uzunahmetler.

Once built however, the railway would reach the Pasinler plain, allowing for better transport of construction materials for the rest of the project.

[12] After long delays, conversion was completed to Uzunahmetler in 1949 and 67 km (42 mi) further to Horasan within two years, opening on 1 October 1951.

[14] The standard gauge railway reached Sarıkamış by 1957, but did not open until the entire line to Kars (and to the Soviet border) was complete.

This was done as part of a 576 km (358 mi) long electrified freight corridor from the iron ore mines at Divriği, to the steel plant and ports near İskenderun.

The electrification would stretch 815 km (506 mi) from Ankara to Çetinkaya, including the three bypasses, allowing for continuous electric operation from western Turkey.