Everybody agrees that BART, at age 44, is struggling — even top BART officials.

“I would say it’s falling apart,” said Paul Oversier, BART assistant general manager for operations.

Once a sleek, Space Age system heralded as the nation’s first high-tech subway and the future of rapid transit, BART today is known for overcrowding, breakdowns and delays.

Trains are so packed, especially during peak commute times, that many riders are forced to stand. Delays occur regularly. Train breakdowns and equipment failures are common, and passengers complain that the trains and stations are dirty and dilapidated.

The transit system’s downward spiral is the fault of many things, including age and surging ridership. But decisions made — and not made — at critical junctures helped propel the system into its current morass. BART estimates that it needs $9.6 billion in improvements — an estimate that’s a couple of years old — just to keep the trains running.

Timeline: BART's journey

Look through this timeline to see BART's progression from a futuristic marvel to a crumbling, 44-year-old system.

BART officials hope voters will overlook past mistakes and approve a $3.5 billion bond measure in the Nov. 8 election, something that’s been described by some as just a down payment toward all that is needed to bring the system up to what it should be.

Bay Area Rapid Transit rolled into existence in 1972 with much fanfare — a shiny new rail system promising modernistic computer-controlled trains, a cushioned seat for nearly everyone, carpeted floors and a smooth, speedy, comfortable commute.

It struggled with its new technology for a few years, but BART eventually settled in and began striving to live up to the goal of transforming the way people move around the Bay Area, using the most up-to-date technology and a modicum of luxury to entice commuters from their cars.

Despite a variety of stops and starts over the past four decades, BART has become an integral part of the Bay Area, carrying growing numbers of riders, enabling some to live without cars, and shaping people’s decisions about where to live, work and build around the bay.

“It started as a thing that was nice to have, something you’d mention riding at a party,” said Randy Rentschler, a spokesman for the Metropolitan Transportation Commission, a regional transportation planning and financing agency. “But now it’s something we need to have. The Bay Area has emerged to be completely dependent on BART.”

A steep rise in ridership in recent years shows how reliant the region is on BART. During an average weekday, BART carries about 433,000 passengers — a 26 percent increase in just five years — and the total often hits 450,000. It was designed to carry about 250,000 riders a day, Oversier said.

While BART officials are pleased, the surge in passengers comes at a difficult time, forcing the system to cope with both growing and aging pains at once.

Well into middle age, many of BART’s systems are decaying. Tamar Allen, BART’s chief maintenance and engineering officer, ticks off the major elements that need to be modernized, replaced or rejuvenated: traction power, which delivers electricity to trains; the computerized train-control system; rails; structures, including subways, elevated trackways and rail yards; stations; and railcars.

To address some of the issues, BART has conducted a series of weekend shutdowns on stretches of rails since last year, but it is just the beginning of the extensive work that needs to be done, Allen said.

“It’s really just the tip of the iceberg,” she said.

This year has been particularly tough for BART with several high-profile problems. In addition to the usual delay-causing troubles, a series of still-unexplained voltage spikes knocked scores of railcars out of service in Oakland and North Concord and shut down the end of the Pittsburg/Bay Point line for days this spring. The problems delayed commuters, forcing them for weeks to take shuttle buses or switch trains. Then they disappeared as suddenly and mysteriously as they appeared.

Early in the year, a killing on a train forced chagrined BART officials to admit that most of their on-board surveillance cameras were either fake, outdated or broken. Officials have promised to install working cameras in every car.

While the structural and mechanical aging issues facing BART have become evident in recent years, the troubles started in the late 1980s and ’90s — when the transit system appeared to be healthy and many people still considered it new, said Jim Wunderman, president and CEO of the Bay Area Council, a business lobbying group that has supported BART from its start.

“Time travels fast,” he said. “Rather than maintain as we went along, we let critical parts of the system age: the rolling stock, but also the train-control system, trackways. Now everything is falling apart. It could have been predicted.”

For almost 10 years starting in the mid-1980s, BART directors failed to take the politically unpopular step of raising fares, depriving the system of money for improvements. That ended in the late 1990s with three years of big fare hikes, totaling 35 percent. The additional revenue was used to renovate BART’s original railcars, and repair and replace elevators and escalators. But it wasn’t enough to make up for the years of stagnant fares.

About the same time, BART and many Bay Area politicians set their focus on extending the system — to Pittsburg/Bay Point to Dublin/Pleasanton in the Tri-Valley and down the Peninsula to San Francisco International Airport. The extensions, now an important part of BART, diverted money away from maintaining the core of the system and from saving money for future improvements. The extensions were popular with local, state and federal officials, as well as riders, but the additional trains increased wear and tear on the existing system.

“If the political will is ‘Let’s build a new extension rather than improve the system,’ operations and maintenance get shortchanged,” said Martin Wachs, professor emeritus of civil and environmental engineering and city and regional planning at UC Berkeley, and head of the university’s Institute for Transportation Studies.

While transit experts and BART officials say the system remains safe and that routine maintenance has not been neglected, key systems will need to be replaced if it is going to stay that way.

“It’s not like we haven’t had a robust maintenance program,” Oversier said. “It’s that the systems we have maintained properly for 44 years have reached the end of their useful life.”

Wachs, who has watched BART from the start, said he doesn’t see BART as a victim of mismanagement but of the challenges of running a transit system with limited funding.

“I see no evidence of malfeasance,” he said. “I see a system that’s been well-maintained but is in need of a major overhaul. I would not interpret the current state of BART as failure.”

BART is not the only large transit agency in the nation to face the challenges of an aging system. Washington’s Metrorail, which opened a couple of years after BART and relies on similar equipment, has suffered deadly derailments and fires. The entire system was shut down for inspections for a weekday in March and dozens of shutdowns of shorter stretches are scheduled. Part of a Chicago Transit Authority line was shut down for five months for track repairs last year, and a section of Baltimore’s subway was closed for weeks this summer for repairs.

Aside from occasional weekend repair work — and a three-month shutdown after a 1979 fire in the Transbay Tube — BART has never had to close its entire system or shut down a line for an extended period of time for breakdowns. But transit experts warn it could happen if BART doesn’t act.

“Look at the large systems everywhere, and it’s the same problem — how do you deal with aging assets and continue to provide the capacity you need to support continued growth?” said Richard White, acting executive director of the American Public Transportation Association and a BART general manager in the 1990s.

And, like BART, many of those transit agencies are asking the voters for help. White said ballots across the country on Nov. 8 will include about $200 billion in transit tax proposals — a record.

BART’s bond proposal, Measure RR, focuses on paying for upgrades to electrical and train-control systems, rails and stations. More glamorous improvements that would benefit the Bay Area, such as system extensions, new stations, a second Transbay Tube and late-night service — estimated to cost tens of billions of dollars — are not included.

Things might have been different but for BART’s biggest oversight, which came as the 1990s drew to a close and the bond measure voters approved in 1962 to build BART expired along with the revenue that came with it. Assessments appeared on property tax bills in the three BART counties for the last time in 1999. And while many cities, school districts and government agencies make it a practice to pass overlapping or back-to-back bond measures to ensure a steady flow of money for costly projects, BART did not.

Tom Radulovich, president of the BART board, said that when he was first elected as a director representing San Francisco in 1996, there was some discussion that because BART had recently turned 20, it needed to start thinking of replacing its infrastructure. But with the fare increases and a focus on extensions, he said, “The politics just weren’t right.”

Later, earthquakes in Los Angeles’ Northridge area and in Kobe, Japan, drew BART’s attention to its seismic safety issues, said Dan Richard, a BART director from 1992 to 2004, now chairman of the California High-Speed Rail Authority board. After a failed attempt in 2000, BART persuaded voters in 2004 to approve a $980 million bond measure to bolster the Transbay Tube, elevated tracks and stations against earthquakes.

But the bond raised nothing to care for the core of the system.

“It’s kind of remarkable that they didn’t go back to the voters,” said Stuart Cohen, executive director of TransForm, a transit advocacy group that has often been critical of BART’s priorities.

Cohen said BART is in the predicament it’s in because of a past failure to plan ahead.

State Sen. Steve Glazer, D-Orinda, a frequent BART critic who opposes the November bond measure, cites its problems as an example of BART mismanagement.

“The deterioration of the system didn’t happen overnight,” he said. “It was a slow-moving train.”

But even if it’s arriving late, the vision at BART appears to have switched tracks — away from extensions and toward rebuilding the core of the system and expanding it to handle the growing crowds riding the trains.

Nick Josefowitz, a BART director from San Francisco, calls it “a cultural change.” He said BART is taking a different approach to keeping up the system — from engaging in periodic weekend shutdowns to getting track replacements done faster, from cataloging its equipment to scheduling maintenance instead of waiting until something breaks to fix it.

“For the longest time at BART, we treated our assets as if they were still basically new,” he said. “But around 2012, we finally got real, realized our assets were not new. It should have happened earlier.”

Transit advocates like Cohen, who have long battled BART over what they considered the neglect of its core, are pleased with the change in emphasis.

“We’re excited that the new focus is to make BART a leading system again,” he said.

Success, of course, depends in large part on the generosity of the voters in November. The ballot is crowded with tax measures, and the two-thirds supermajority needed for the BART measure to pass is a difficult standard to meet.

“We’ll see if it passes,” Radulovich said. “There might be a chance we have to try twice. But I really don’t see another path forward.”

Michael Cabanatuan is a San Francisco Chronicle staff writer. Email: mcabanatuan@sfchronicle.com Twitter: @ctuan

Transit district bond measure

Voters who live in the Bay Area Rapid Transit District — San Francisco, Alameda and Contra Costa counties — will decide Nov. 8 on a $3.5 billion bond measure to fund rehabilitation and modernization of the aging BART system. To pass, Measure RR needs combined approval from two-thirds of the voters who cast a ballot in the three counties.