Officials said they believe a signal failure may have caused the crash, or collision.

官员们表示，他们认为可能是导致了列车相撞。

Local media report accidents with dozens of injured due to malfunctioning traffic lights.

当地媒体报道了交灯导致数十人受伤的事。

All eastbound trains have been cancelled due to faulty signals.

【bound】由于，所有东行列车均已取消。

So, while the horn is primarily a means  of communication, it is not the only way the aircraft can send a signal, to warn of  failure.

因此，虽然喇叭主要是一种方式，但它并不是飞机发出警告的唯一方式。