It seems the air conditioning on the ELL trains may not be able to cope with the wrong sort of weather - ie warm. On three of the four trains I travelled on yesterday (Sunday opening day), the a/c had failed due to overwork, in at least part of the train. Since you can't open the windows this makes the train uncomfortable to say the least. And although yesterday was warm, it wasn't exceptionally hot, and the trains weren't exactly loaded to peak hour capacity. Apparently LOROL are aware of the problem and a modification is planned. I've requested details of the modification plan. In the meantime, it might be a good idea to dress lightly and have some water with you...