A railway grinding machine under KiwiRail contract sparked two separate fire callouts at the weekend.

Fire service spokeswoman Tania Matthews said the callout to Holland Rd, Puketaha, yesterday morning was in the same location as a fire the previous day. The fire was caused when sparks flew into vegetation from the machine that ground corrugations off rail lines, she said.

"Some scrub had caught on fire and there were a few small fires that were deep seated, but it was eventually brought under control. It was smouldering when we got there and there was a lot of ash which indicated it had been burning."

Hamilton Fire Brigade spent more than an hour at the location east of Hamilton.

Speno Rail Maintenance Australia has the $8 million rail rectifying contract and shipped a $15m grinder across the Tasman in October for the two-year job.

The machine crawls along the tracks at between 3kmh-10kmh with sparks swarming under its carriage.

It has 24 grinding motors on it - 12 on each rail - that push an aluminium oxide grindstone to 3500 revolutions per minute. From 0.2 to 0.5mm of rail is carved off and, after up to five passes, it's a smooth ride.

The sparks are so thick, the track has to be simultaneously dampened to douse any flames but in both cases at the weekend the fire brigade was needed.

The job started in Waikato because it is in the "Golden Triangle" of trade. KiwiRail's east coast main line is a priority because it carries 8.5 million tonnes of cargo from Hamilton to Tauranga a year.

matt.bowen@waikatotimes.co.nz

- © Fairfax NZ News