|
| Factor | Attribute | References |
|
| Accessibility | Access to metro stations (C1) | Brons et al.[32], de Oña et al.[33] |
| The smooth functioning of the tollgate (C2) | Aydin et al.[1] |
| Access and condition of escalators (C3) | Nathanail[34], Brons et al.[32] |
| Ticketing service | Vending machines (C4) | Vuk[33], Aydin [35] |
| Ticketing system (C5) | Aydin et al.[1], Geetika [8] |
| Information service system | The usage of modern equipment in station services (C6) | Aydin et al.[1], Nathanail[34] |
| The usage of modern equipment inside the train services (C7) | Aydin et al.[1], Machado-León et al.[12] |
| Announcements in stations and trains during and after breakdowns (C8) | Aydin et al.[1], Litman[2] |
| station comfort | Cleanliness of metro stations (C9) | de Oña et al.[13] |
| Lighting of the stations (C10) | Aydin et al.[1] |
| Comfort level in stations (C11) | Aydin et al.[1], Garrido and De[27] |
| train comfort | Cleanliness inside the trains (C12) | Aydin et al.[1], dell’Olio et al.[36] |
| Noise level and vibration during the journey (C13) | Brons et al.[23] |
| Air-conditioning system inside the trains (C14) | Aydin et al.[1], Geetika [8] |
| Train crowding (C15) | Machado-León et al.[12], Vuk[35] |
| safety | Safety at stations (C16) | Aydin et al.[1], Nathanail[34] |
| Sense of security against accidents while traveling (C17) | dell’Olio et al.[13], Aydin [35] |
| time | Waiting time for metro before departure (C18) | Aydin et al.[1], Gerçek et al.[37] |
| Journey time (C19) | Shen et al.[21], Yilmaz et al.[22] |
| Itinerary accuracy (C20) | Aydin et al.[1], Chou et al.[20] |
|
