There are the five trains that are supposed to pass on four tracks over the Charles River within just a few minutes of each other.
And there are two trains that sometimes arrive at the same, single-track tunnel at the same time in Salem.
And then there’s the train that spends more than 40 minutes going backwards and idling before finally heading to Boston.
All are examples of the built-in flaws in the schedule that make it nearly impossible for some of the T’s commuter rail trains to run on time. Now, for the first time in decades, the MBTA says it is preparing to release new systemwide schedules that officials hope will cut down on delays and other inconveniences for riders.
“Now we’re able to remove those conflict points in our existing schedule, and remove those causes for delay going forward,” said Frank DePaola, the general manager of the T.
The MBTA will publicize the new schedules by the end of the month, and they will go into effect around Nov. 30.
Though an outside operator, Keolis Commuter Services, runs the commuter rail, the MBTA sets and approves the schedules. Keolis officials say they inherited several “scheduling anomalies” that affect service.
T officials said the changes to the schedules to be released this fall will be minor — departure times won’t be drastically different from those to which commuters are accustomed — but they are expected to significantly reduce delays.
With the current schedules, it is possible for trains to run on time, but only under perfect conditions, said John D. Ray, the MBTA assistant general manager for commuter rail. Common events such as heavy rain or snow, a freight train from another company, police activity, medical emergencies, or a signal problem can throw everything out of whack.
“There are a lot of things that the railroad doesn’t control,” Ray said. “We know that they’re going to happen, so we can’t run perfection each day.”
Ray said that the new schedules are engineered so that one delay does not lead to a cascade of other delays. He said the new schedules will allow for more time between the train’s arrival at the end of the line and its departure on a new trip.
The extra turnaround time will reduce traffic jams caused by unexpected delays.
Ray said commuters should expect even more rush-hour trains. He also said that he guaranteed that commute times would be the same for most riders, or even shorter.
The changes were presented at a meeting of the fiscal control board, the body that oversees the T, and only covered lines that operate out of North Station. Officials will release more details on their plans for lines that run out of South Station later this month.
Also at Monday’s meeting, T officials said they will consider reversing the ban on alcohol advertisements on MBTA trains and in stations. Brian Shortsleeve, the T’s chief administrator, said allowing such advertisements could bring in more than $1 million in revenue.
The T banned alcohol advertising in 2012, not long after a youth group against substance abuse rallied for the change. Mayor Martin J. Walsh, who was a state representative at the time, had also proposed legislation that would bar alcohol advertisements on state-owned property.
The MBTA currently bans 15 categories of advertisements, including alcohol, tobacco, and firearms.
Officials for the T did not propose any changes to the policy on Monday, but presented data that showed the T would not be alone in allowing such advertisements. Other large metro transit agencies — in Chicago, New Jersey, and Minneapolis, for example — allow alcohol ads. Shortsleeve also pointed out that bus shelters owned by the city of Boston also carry advertisements for alcohol.