Madrid, Spain (CNN) -- In advance of the seventh anniversary of the Madrid train bombings, ambulance technician Esther Lopez went back for the first time to the scene where she aided the wounded and transported the bodies of the dead.
There was a feeling of "powerlessness because Madrid's emergency services were overwhelmed. No one expected it. But the emergency services and the public did everything possible to lend a hand," Lopez said about the attacks on March 11, 2004.
The Madrid train bombings -- coordinated attacks on four morning-rush commuter trains -- killed 191 people and wounded more than 1,800.
Spanish courts have convicted 14 Islamic militants for their roles in the attacks, along with four Spaniards, the latter for trafficking in explosives used in the attacks.
Memorial ceremonies for the victims on Friday, the seventh anniversary, are expected to be low-key, in keeping with recent years in Madrid.
Madrid's mayor will inaugurate a monument to the victims who were killed or injured at Pozo station, where one of the four trains was bombed.
Lopez and her ambulance crew were called to duty that day at another location, Tellez Street, a section of tracks where bombs exploded on a second train just before it entered the main Atocha station, where bombs also went off on a third train. There is already a large monument to the victims at Atocha.
The fourth train was struck at the Santa Eugenia station, which like the other locations is on a commuter line connecting eastern Madrid and the downtown Atocha terminus.
Lopez and her fellow crew members were just finishing their once-a-week 24-hour shift at their base in suburban Las Rozas when an urgent call came from an emergency coordination center requesting all available units to go to the scene of the bombings, Lopez said.
At Tellez Street, the injured were taken from the tracks to a nearby sports center converted into a field hospital. Video that day from CNN affiliate CNN+ showed Lopez and her team rushing an injured woman to hospital.
"The patient died," Lopez said, standing outside the sports center last week, just before the anniversary. "The patient was one of the most seriously wounded."
After that trip to the hospital, Lopez's crew returned to Tellez Street, where their large, orange civil protection tent, usually used as a field hospital, became a temporary morgue.
For much of the rest of the day, they helped identify and move bodies.
"The funeral service and ambulance drivers got as close as possible when we brought out the body bags," Lopez recalled.
Later, she thought about quitting her job, and she still tries to leave Madrid on the bombing anniversary. Many victims, as well as close relatives of people killed that day, have told CNN they, too, try to leave town on the anniversary day.
"My mother has a lot of pictures from that day and I still haven't been able to look at them," Lopez said.
Two other members of Lopez's ambulance crew that day -- technician Alvaro Garcia and nurse Laura Santiuste -- have since gotten married and had a baby. They say they've come to terms with that day.
But for Lopez, it has taken longer. At the sports center, a plaque honors the victims and praises the courage of the emergency workers.
Lopez saw it for the first time last week and said, "Just a simple 'thanks,' like it says there, is plenty in return for what we went through that day."
The Spanish Interior Ministry said Thursday the government has paid, since 2004, a total of 314 million euros (about $434 million) in indemnities to the victims or their surviving family members. Some of these payments went to non-Spaniards among the victims, and involved analyzing inheritance laws in 16 other nations.
The government has also provided 3.3 million euros ($4.5 million) to organizations that have special programs of attention for the victims.
The National Court in 2008 determined that the terrorists convicted in the attacks did not have sufficient funds to pay damages to the victims, the ministry said.