and a Ferrocarril Suburbano smart card is required for access. Another commuter rail, Tren Interurbano de Pasajeros Toluca-Valle de México is estimated to be completed in 2023. This line will connect Observatorio station in Mexico City with Toluca. Fares and pay systems A single ticket, currently MXN $5.00, allows a rider one trip anywhere within the system with unlimited transfers. A discounted rate of MXN $3.00 is available upon application for women head of households, the unemployed, and students with scarce resources. Mexico City Metro offers free service to the elderly, the physically impaired, and children under the age of 5 (accompanied by an adult). Tickets can be purchased at booths. They are made of paper and have a magnetic strip on them, and are recycled upon being inserted into a turnstile. Until 2009, a STC Metro ticket cost MXN $2.00 (€ 0.10, or US$ 0.15 in 2009); one purchased ticket allowed unlimited distance travel and transfer at any given time for one day, making the Mexico City Metro one of the cheapest rail systems in the world. Only line A's transfer in Pantitlán required a second payment before 13 December 2013. In January 2010, the price rose to MXN $3.00 (€ 0.15, or US$ 0.24), a fare that remained until 13 December 2013; a 2009 survey showed that 93% of citizens approved of the increase, while some said they would be willing to pay even more if needed. STC Metro rechargeable cards were first available for an initial cost of MXN $10.00. The card would be recharged at the ticket counter in any station (or at machines in some Metro stations) to a maximum of MXN $120.00 (around € 6.44, or US$ 7.05 in 2015) for 24 trips. In an attempt to modernize public transport, in October 2012, the Mexico City government implemented the use of a prepaid fare card, or stored-value card, called Tarjeta DF (Tarjeta del Distrito Federal, literally Federal District Card) as a payment method for STC Metro, Metrobús and the city's trolleybus and light rail systems, though they are all managed by different organizations. Servicio de Transportes Eléctricos manages both the Xochimilco Light Rail line and the city's trolleybus system. Previous fare cards that were valid only on STC Metro or Metrobús remained valid for the system for which they were acquired. Rolling stock As of April 2012, 14 types of standard gauge rolling stock