Volume Eleven - Pre-Victorian to the Present Day - some more aspects - The Steam Navvy and the Dock Extension of 1883 . . .

The size of the excavation, the material, the facilities for tipping, &c., will in each case determine which system can be used with the greatest advantange. With the hardest and most tenacious clay, about 22 ft. is the best depth, as then no wedging down is required of the stuff above the reach of the bucket teeth. With loose earth 30 ft. can be just as easily taken, since it all falls down to the machine. Within these limits, the deeper the face the better, as the greatest quantity can then be scooped out between each forward movement.

To stop, ease the jack-screws, lay rails, run the navvy forwards, tighten down the screws, and get to work again, requires from five to ten minutes, during which of course no wagons are filled. The fewer the stops in the day, the greater will be the number of wagons filled ; and the larger the quantity of material within reach of the bucket, the less seldom need the navvy be moved forwards.

June 1883 - A reminder of the Penarth Dock Extension Works with steam navvies at work. [007] [599]