1 TRACK QUALITY INDEX AS TRACK QUALITY ASSESSMENT INDICATOR Dian Setiawan M Civil Engineering Department Faculty of Engineering Universitas Muhammadiyah Yogyakarta Jl. Lingkar Selatan, Tamantirto, Kasihan, Bantul, Yogyakarta, 55183 dian_setiawanm@yahoo.co.id Sri Atmaja P. Rosyidi Civil Engineering Department Faculty of Engneering Universitas Muhammadiyah Yogyakarta Jl. Lingkar Selatan, Tamantirto, Kasihan, Bantul, Yogyakarta, 55183 atmaja_sri@umy.ac.id Abstract Track Quality Index (TQI) is used in order to evaluate track quality. In this paper, TQI application for Indonesian Railway (IR) has been reviewed and various methods to evaluate track quality have been presented. IR have been used TQI-Geometry in infrastructure maintenance works and accident investigation. UK SD Index, Netherlands Q Index, USA TRI, FRA TGI, Austrian TGI, Canadian TQI, SNCF’s MDI, Chinese TQI, Polandia J Coefficient, Indian TGI, and European Standard are some methods to evaluate track quality. However, their results rely only on a limited number of parameters and aspects of track deterioration. Those methods cannot provide a thorough indication of all influencing parameters and their role in track degradation. The author suggests that main track degradation should have 4 aspects: Track Super-Structural; Track Sub-Structural; Track Geometrical; Traffic, and furthermore, a new TQI should be developed by combining 3 index investigations: Track Irregularity, Track Settlement, and Track Geometry. Keywords: Track Quality Index, Track Degradation, Track Structure, Track Geometry, Traffic Parameters Abstrak Track Quality Index (TQI) digunakan untuk mengevaluasi kualitas jalan rel. Penelitian ini membahas penggunaan TQI dalam perkeretaapian Indonesia dan menyajikan berbagai metode yang digunakan untuk mengevaluasi kualitas jalan rel. Perkeretaapian Indonesia menggunakan TQI-Geometrik pada pekerjaan pemeliharaan infrastruktur dan investigasi kecelakaan. UK SD Index, Netherlands Q Index, USA TRI, FRA TGI, Austrian TGI, Canadian TQI, SNCF’s MDI, Chinese TQI, Polandia J Coefficient, Indian TGI, dan European Standard merupakan beberapa metode lainnya yang dapat digunakan untuk mengevaluasi kualitas jalan rel. Namun, hasil dari metode-metode tersebut hanya terbatas pada beberapa parameter dan aspek kerusakan jalan rel dan juga tidak dapat menyajikan indikasi terperinci dari semua parameter yang berpengaruh dan perannya terhadap kerusakan jalan rel. Penulis menyarankan kerusakan jalan rel sebaiknya terdiri dari 4 aspek: struktur atas jalan rel, struktur bawah jalan rel, geometrik jalan rel, dan lalulintas, serta selanjutnya dikembangkan TQI terbaru yang merupakan kombinasi dari 3 investigasi index: Track Irregularity, Track Settlement, and Track Geometry. Keywords: Track Quality Index, Kerusakan Jalan Rel, Struktur Jalan Rel, Geometrik Jalan Rel, Parameter Lalulintas INTRODUCTION The construction of railway networks involves a large amount of financial support imposing, not only at the conception and design level, but also during the line operation, a demanding, a complete, and a rigorous estimation of the total cost involved in the life cycle of the system. Furthermore, due to the running of high-speed trains and heavy haul trains, the track equipment is damaged more frequently, leading to a threat of running safety. However, maintenance of railway tracks is both costly and difficult to manage effectively.