In the following identify the correct statements about the Konkan Railway.
(A) It was constructed in 1998.
(B) It connects Roha in Maharashtra to Mangalore in Karnataka.
(C) It is considered an engineering marvel.
(D) The states of Maharshtra, Tamil Nadu and Karnataka are partners in it.
Choose the correct answer from the options given below:

The correct answer is (A), (B) and (C) only.

Let us evaluate each of the statements to understand why this option is correct:

Statement (A) is correct: The Konkan Railway was constructed and formally inaugurated on January 26, 1998, connecting the region to the national rail network.

Statement (B) is correct: The railway line links Roha in Maharashtra to Mangalore (Mangaluru) in Karnataka, covering a distance of about 760 kilometers along the western coast of India.

Statement (C) is correct: It is widely celebrated as an engineering marvel because its construction required overcoming massive geographical challenges in the Western Ghats, which involved building 91 tunnels, over 2,000 bridges (including the tall Panval Nadi viaduct), and navigating numerous rivers and unstable, landslide-prone soils.

Statement (D) is incorrect: The partner states in the Konkan Railway project are Maharashtra, Goa, Karnataka, and Kerala. Tamil Nadu is located on the eastern coast of the southern peninsula and is not a partner state in this western-coast railway system.

Thus, statements (A), (B), and (C) are correct, while statement (D) is incorrect.