That’s the sound of the emotional roller-coaster I’ve been riding for the past seven months with these teenagers. That was the sound it made as it plummeted last week towards ground zero.

The problem is that it is nobody in particular with their hand on the control stick, not me, not the kids, nor the street educators. Their is nobody to blame – the machine bumps and rolls, advances and reverses under circumstance. And circumstance is not in anybody’s control.

Here follows the story of the last two weeks.

A week after the events of the last entry (Public Space Invasion), Mauricio and I arrived at the Casa Alianza gates at 8.45am to be warmly greeted by a deserted street; nobody from the week before had turned up, not even Miguel Ángel. As we sidled along behind the street educators, en route to a pair of newly found young girls, Mauricio made those dreaded words, already ringing silently in my head, into tangible, regrettable sounds: “Ali, this isn’t working”.

We crossed through a food market in Garibaldi Square, where the sombreroed mariachis come to sing and the restaurateurs chime out their menus. In one booth not yet open, beneath the littered tables and overturned stools, we found the sought out girls, heaped together with worn, stinking blankets and tightly clad in last night’s hotpants, Hola, Catarina. Hola, Maria Antonia. They greeted us sleepily, flattening out their hair and readjusting their clothes. After this brief introductory meeting, they reluctantly agreed to join us back to the Casa Alianza HQ with the promise of a change of clothes, some breakfast and a hint of photography.

A surprise awaits around every corner in this job and that day was no exception. On our return to HQ we caught sight of Gerald, the Belizian boy who had unexpectedly turned up the week before after his escape from the home. A week on the streets had taken its toll, he looked a little rougher, a little older, although he had smothered the signs with fresh make up. Alongside him was a boy I had seen now and again around the Alameda Park, well known for its wealthy supplies of under-age gay prostitutes. His name was Francisco Javier, he was clean, smiling and enthusiastic.

Huddled in the back office with our three new members and Gerald, Mauricio once again magicked up his ice-breaker, the Foto Buzón postcard photos. Maria Antonia made it her intention to show as little interest as possible, although she eventually warmed to it. Catarina, on the other hand, picked out this photo and stared at and searched it for minutes. Just like Itzel from the week before, she said it reminded her of home, she is from the state of Michoacan. She also noted the young bullfighter practising with his cape, and this seemed to make an impression on her. With the ice now cracking, we decided to give it a final breaking blow with the digital cameras; we hung up the black background and had the three of them snapping away, first at me, then at each other. To me, it seemed Catarina was totally captivated.

Francisco Javier getting into his role as photographer.

Catarina's portrait bi Francisco Javier

After this successful first encounter, Mauricio and I did not lose any time in arranging a second meeting for the next day.  Gerald (quite inexplicably and very obstinately) refused and Maria Antonia violently shook her head; they had not been taken by the impromptu workshop and true to their word, they did not arrive the next day. Catarina and Javier, by contrast, happily joined us. My roller-coaster ride was trundling up a steep incline, jittery and slow, but heading towards a sunny sky. Our second workshop took us to the Revolution Plaza with its great monument to the ideologies of that movement, and it was here that I listened intently and with wonderment to Catarina’s inspired interpretations of the images Mauricio had given her. She pored over those photography books, savouring every image; when she spoke about them, she spoke of religion, poverty and the human condition. If anyone knew of these things, it was she and she was articulating them well. My roller-coaster was ascending faster now, hyped by a cork-screw twist in the track. The next hour Catarina and Javier spent wandering the Plaza, each with a disposable camera, choosing their own moments to freeze in time.

These images were a practice for the second set of disposable cameras that I gave them. This time I took a different approach. I asked them to specify a story they wanted to tell, not necessarily about themselves, but to create a narrative with these cameras, similar to the ones they’d seen in the book. Javier said that he wanted to tell the story of the people who work in the rubbish dumps of the city. Catarina wanted to tell the story of the children of Tepito, a notoriously dangerous zone in Mexico’s Federal District and the place where she resides.

That was the peak, and then came the inevitable plummet. Last week neither Javier nor Catarina appeared with their cameras. We looked for them; José Juan and I trawled Tepito, shuffling between its hoards of black-market stalls and searching the groups of faces of the youngsters who shelter beneath them at night. Outside the soup kitchen that Catarina goes to for lunch, we found Maria Antonia. She told us that Catarina had been taking photos, but that she’d disappeared two days ago without a word and Maria Antonia didn’t know where to. No one had seen Catarina. And Javier, who had been turning up at the Casa Alianza gates regularly for weeks, was not to be found. He hadn’t been seen outside Casa Alianza that week at all. We circled Alameda Park, asked the men adorned with their heavy eyelashes if they had seen little Francisco Javier, no, they told us, not for a while, although someone mentioned they had seen him in the waiting room of the HIV hospital. Via these contacts we passed on messages to both participants, but I could feel my roller-coaster hitting ground level and slowing down towards the exit sign.

That said, I won’t be disembarking this ride for a couple of months yet, and so the best I can do is keep my seat and wait for the next go. It is sure enough that a couple more loop holes await me ahead. It is still even possible that Catarina and Javier might appear to accompany me for a second go on the ride.

Catarina spots a parallel Kodak moment.

"The Thinkers" by Javier

A lone passerby, by Javier

Javier looks below for inspiration.

Javier shoots the square from a new perspective

My favourite by Javier of the street cleaners.

Catarina looks up for inspiration.

Catarina's ground shot of the Monument - shame about the tiny little bit of finger!

Catarina runs with the dog, and just manages to get him.

"The Boys" by Cata

My favourite by Catarina: a perfectly framed and captured facial expression.