Updated

The California Public Utilities Commission has ordered a downtown Los Angeles trolley with a short ride and a long history of problems to shut down until it can sort out its latest passenger safety issue.

Following an inspection Thursday, operators of Angels Flight were verbally ordered to find the cause of an unsafe deterioration in its steel wheels and make repairs. A written letter will be issued Friday, according to CPUC.

"CPUC inspectors, in a routine inspection, found that the wheel flange, which holds the wheels of the cars on the rails, have deteriorated to the point of being unsafe," according to a statement from CPUC.

The railway's own mechanics and consultants were surprised to find that the railway's steel wheels were wearing down more quickly than expected and the wear "had accelerated in the last month to a point where replacement is required sooner than the normal time period expected for steel wheels," said Railway Foundation president John Welborne in a statement.

The wheels may take several weeks to replace, as "they are custom items, not available just off-the-shelf," said Welborne.

Over the last 15 months, the trolley has been operating sixteen hours a day, seven days a week to provide about 800,000 passenger trips, he said.

The Angels Flight is dubbed "the shortest railway in the world" and takes passengers for a 298-foot ride up or down a steep hill in the city's Bunker Hill area.

Riders have boarded orange and black wooden cars since 1901 to ride the funicular, which means its two passenger cars are connected by a cable and move up and down the tracks simultaneously.

When the railway opened, the ride cost a penny and took residents from the Victorian mansions of Bunker Hill to the shopping district at the bottom of the hill.

Over time, the area became a slum and was razed in the 1960s to make way for skyscrapers, hotels and apartment buildings. The railway was dismantled in 1969 and sat in a warehouse for decades until it was reassembled in 1996 a short distance from the original location.

But tragedy struck in February 2001 after a car rolled uncontrollably downhill and hit another car, killing an 83-year-old man and injuring seven others. The 25-cent rides were halted until March 2010 as a result.

An investigation faulted a modern gear that had replaced an original part, causing a cable that raised and lowered the car to come off its spool. The emergency brake was also broken.

It took years for the Angels Flight Foundation to raise the $3.5 million needed to repair and upgrade the railway to reopen it.

"Charging only a quarter is something we are not sure is going to be possible for too much longer," said Welborne.

Wearing a trainman's vest, Chris Pobanz sat in the orange pagoda that serves as Angels Flight's top-of-the-hill ticket booth on Thursday evening.

Normally, he sells tickets and operates the car for hundreds of passengers a day. On Thursday, he planned to stay until 10 p.m. to turn people away as the trolleys sat idled on the track.

From his perch atop Bunker Hill, overlooking the twinkling lights of downtown buildings, he said of the fruitless hours ahead, "at least the view is nice."