Complex sentence: Arriving at Creekoor Halt, alas, he saw no engine, but Trevor, falling about laughing hysterically poining to large Hi-Fi speakers he had placed outside his bedroom window.
Split into simpler sentences: Arriving at Creekoor Halt, alas, he saw no engine, but Trevor, falling about laughing hysterically. He pointed to large Hi-Fi speakers he had placed outside his bedroom window.