Also passengers with kids under 3 years of age can ride for free.
Ten of the 20 passengers riding on top were killed.
Officials expect that 1,400 passengers will ride the new service daily each way by the end of the third year.
More than 50 million passengers still ride trains in America every year.
The passenger riding along between my ears had told me not to try to talk to him until we were clear of the city.
In 2011, more than 17 million passengers rode the metro.
About 25,000 passengers rode the line Saturday when it opened to the public.
On the first full day of service, 3,300 passengers rode the new University buses.
Nearly nine million passengers rode the $1.9 billion rail system last year.
To either side of the engine were two areas in which passengers could ride or stores be carried.