Noisy Gautrain

I have been travelling on Gautrain for many years. Slowly but surely the service and the maintenance has deteriorated over time. Today I travelled in a carriage numbered 30015. I moved to this carriage because the speaker in the carriage I was in made a squawking noise that was difficult to describe except that one might compare it to finger nails on a blackboard. Having moved to carriage 30015 I found that as the train moved over the tracks one periodically felt as though the carriage was going to shake apart. I doubt there was any danger of that, but it did not make for a pleasant journey. To add insult to injury it seems that many passengers have no problem with playing loud music, so loud that their earphones do not prevent their fellow passengers from hearing the resulting duff, duff, duff...Things were not like this 5 years ago, why have things slipped so badly?