Now that we're starting to see signs of spring, waiting outside for the regional rail, bus, subway, or trolley has become a much more pleasant experience.

But weather aside, some changes are coming to Philadelphia mass transit thanks to initiatives in progress at SEPTA.

The agency is looking into buying "articulated trolleys,' which are longer than regular trolleys and can bend in the middle through turns. They also will be wheelchair-accessible, which current city trolleys aren't.

But some engineering and maintenance challenges could spell trouble for the articulated trolleys, according to Jim Saksa, transportation reporter for PlanPhilly, a project of WHYY.

"There are a lot of issues that SEPTA's only just now trying to figure out," he said, adding that it would be at least five years before any Philadelphians see articulated trolleys in use.

What's more of a done deal is implementation of new bilevel trains for SEPTA's regional rail lines, which Saksa says could appear by the end of 2018.

"[SEPTA is] already looking to procure them. The engineering issues in terms of clearance are pretty minor," he said.

Also coming up on SEPTA's docket is a new "smart" payment system, which will now be designed so low-income residents' fare cards double as debit cards that accept direct deposit payments.

Finally, the University City District is experimenting with new ways of constructing public seating at a SEPTA stop at 36th and Lancaster. Saksa says this is all part of the UCD's increased efforts of "placemaking."

"It's the idea of really making an area a place that you want to interact with and engage with, and key to that is seating," he said.

Taken together, these changes could mean a new experience for SEPTA riders in the coming months and years.