Ride on (MRT)

What I Want To Know 

• Are there any drivers?
• How many drivers are there?
• What they used to make the train work?
• Why does the MRT breakdown?
• Largest possible number of passengers?
• Why sometimes it goes underground and other times above ground?
• How many carriages are there?
• How many seats?
• Does it contribute to air pollution? 
• Do people appreciate that the MRT is very convenient or complain about the breakdown?
• How does the MRT look like in the past?
• How many wheels are there?
• Can it be more than 6 carriages?
• Length of MRT?