For this week's ASK SEPTA column, SEPTA GM Jeffrey Knueppel wrote this letter to SEPTA riders explaining the changes recently made to several Regional Rail schedules — most of which revolve around the Airport line  and why SEPTA had to make the changes.

SEPTA GM Jeffrey Knueppel: SEPTA is receiving questions from riders about the new Regional Rail schedules that go into effect this week.

SEPTA makes Regional Rail schedule changes several times each year; however, those that went into effect yesterday – and that many riders are adjusting to today – are more significant than any we’ve done in recent years. The most noticeable are connected to the Airport Line, but these are overall system changes designed to enhance service reliability across SEPTA’s Regional Rail network.

Related link: Big changes on SEPTA Regional Rail lines coming

SEPTA has recently seen an unacceptable drop in on-time performance on the railroad. For more than a year, we have been analyzing data to pin-point the problems and identify solutions. That led us to implement these revisions co nnected to the Airport Line.

Before this schedule change, the Airport Line was linked with the West Trenton and Warminster lines – both very long routes with high, and growing, ridership. Any problems West Trenton and Warminster trains had impacted Airport Line service. Likewise, problems on the Airport Line would delay West Trenton and Warminster trains. And with these and other rail lines sharing interlockings – points where trains converge – we would often see a cascading effect, with delays spreading onto additional lines that were otherwise running on time.

Related link: Ask SEPTA: Baby strollers on the train and more

By separating the Airport Line from the West Trenton and Airport Lines, and simultaneously implementing a number of timetable changes system-wide, SEPTA can deliver more reliable service to customers. We’ll be analyzing impacts of this change, along with customer feedback, to guide us on additional changes as we move forward.

We understand some Airport, Warminster and West Trenton Line customers will have to make changes to their daily commutes due to the new schedules. For instance, customers who previously used the Warminster or West Trenton Lines to travel to the Airport or University City may need to transfer at Suburban Station to an Airport, Media/Elwyn or Wilmington/Newark Line train to complete their trips.

To assist riders with adjusting to the new schedules, signage has been posted at stations along the impacted lines. SEPTA Ambassadors will also be out at stations this week to help direct passengers and answer any questions.

We urge all customers to check our website, www.septa.org, to view and download the new timetables.

Metro regularly runs "Ask SEPTA," a column of reader questions answered by SEPTA GM Jeffrey Knueppel. To get your question answered by SEPTA, please email it to sam.newhouse@metro.us.