You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Economy_of_Greece

Context:
Greece's rail network is estimated to be at 2,548 km. Rail transport in Greece is operated by TrainOSE, a subsidiary of the Hellenic Railways Organization (OSE). Most of the country's network is standard gauge (1,565 km), while the country also has 983 km of narrow gauge. A total of 764 km of rail are electrified. Greece has rail connections with Bulgaria, the Republic of Macedonia and Turkey. A total of three suburban railway systems (Proastiakos) are in operation (in Athens, Thessaloniki and Patras), while one metro system is operational in Athens with another under construction.

Question:
How long is Greek's rail network estimated to run?

2,548 km