 Several years later a branch line was taken through an bridge beneath the Cornish Main Line to serve new china clay processing works.As well as the very low bridge, this line had a tight radius curve; these two restrictions had to be taken into consideration when buying locomotives to work at the harbour.The first steam locomotive to be put to use by the Treffry Estates was a small four-wheel vertical boiler locomotive built by Sara and Burgess in Penryn in 1912 that arrived at Par the following year.