Sleepers and the sleep

The cat arranged itself on her lap and started up its motor, an uneven circular gurgle. It pressed its warm belly into her own and laid its head in the crook of her arm - her hands wrote at the table before them both. They settled in for a mornings work at the desk.

That night, their sleep was undermined by the sounds of a constant toil as new sleepers were laid on the railway tracks at the end of their street. It was not a nosiy undertaking. It was the murmuring work of the night. Some persistent, repetitive process that grazed through their dreams. Towards the end of the procedure a train must have used the adjacent tracks, and it and the vehicle used to re-place the sleepers, tooted at each other a formal work code or some dark morning joke between the drivers?