Locomotive haulage underground at this pit is the first locomotive coal-haulage scheme to operate in County Durham. The introduction of diesel haulage is the first part of a reconstruction programme planned to be completed by December, 1949. Preparatory work was begun in June, 1943, and the locomotives started work in February, 1948.

The seams wrought are the Maudlin, 1 ft. 3 in. to 3 ft. 0 in. thick, the Low Main, 2 ft. 4 in. to 6 ft. 0 in., and the Hutton, 2 ft. 4 in. to 4 ft. 0 in., the Hutton is about 50 ft. below the Low Main, and the Maudlin 3 ft. to 40 ft. above Low Main. The parting between these two seams is a metal band and the Low Main has a seggar floor about 5 ft. thick. Owing to its thickness the earlier workings were in the Low Main, the next in the Hutton, and the Maudlin is a relatively recent development except where it has been worked together with the Low Main. The main artery is a crosscut in the Low Main seam, rising south-westerly from the shaft at an average gradient of 1 in 43 for 1,450 yards to the Fourth Bankhead. Small sections of Hutton and some Low Main are wrought on the north side, but the chief developments, and the developing area, are to the south.

Before the introduction of the locomotives, the main haulage was wrought by four 100 h.p. haulages :–

All secondary haulages, about a dozen in all, are 40 h.p. main-and-tail and there are several smaller Pikrose haulages. The introduction of locomotives is to be in three main steps, first from pit-bottom siding to Fourth Bank, cutting out two 100 h.p. endless haulages ; second, by a new connection in the Low Main seam which will give a locomotive road about 1,200 yards long to the south and will replace one 100 h.p. main-and-tail haulage. Thirdly, but depending on the proved section of the Maudlin seam, it is proposed to carry the main crosscut on from Fourth Bankhead to connect with the main roads south in order to replace the other 100 h.p. main-and-tail haulage. The existing haulage roads are 12 ft. wide for endless haulage, 8 ft. for main-and-tail.

The locomotives require a height of 7½ ft. and a width of 9 ft. on the double track. This has entailed an average bottom ripping of 2 ft. in the seggar floor or roof of the Low Main crosscut on the new south road it will involve widening Out from a 5 ft. by 5 ft. road to the dimensions specified. Standard main road Supports are "H" section girders 10 ft. by 6 in. by 5 in., spaced 3 ft. apart and supported on wood chocks or brick walls.

The section on which the locomotives are now working from pit bottom to First Bankhead, being close to the shaft, presented a special problem. The road is 14 ft. wide and is supported by girders 16 ft. by 10 in. by 8 in., resting on 20 in. by 5 by 5 in. chocks of hardwood, filled in with brickwork. The grade here averages 1 in 25. The pit-bottom sidings are graded at 1 in 30. The full side is three-track, 120 yards long, with standage for 200 tubs; the empty side is being duplicated to afford standage for 120 tubs and is being fitted with a creeper, rising 22.58 ft. in a length of 128 ft. The introduction of the locomotives cut out the first of the 100 h.p. haulage and saved six men.

This scheme is an excellent example of modernisation of haulage with minimum alteration to tubs and track. The standard haulage rail is a 28 lb. rail, 15 ft. long, of 2 ft. 2 in. gauge, and this will be retained for empties wherever they run on a separate track from the full tubs, as in the Low Main crosscut. For full tubs on locomotive roads, 40 lb. 18 ft. rails will be installed. Sleepers are 4 ft. by 8 in. by 3½ in., laid 3 ft. apart, except at joints, where a sleeper is laid 4 in. on each side of the joint. We took especial note of the twisted nail supplied by a local firm, Dunford Bros., which affords a much firmer grip of the sleeper than the ordinary plate nail.

Wood tubs are used, of 4 cwt. tare, carrying a standard load of 9 cwt. of coal.

The three locomotives, of which one is standby, are Ruston & Hornsby 48 h.p. 7-ton machines with two speeds, the standard running speed being 8 miles per hour. On the present section they are drawing sets of 35, though the makers believe that sets of 90 could be handled. Two locos running 22 shifts a week use 50 gallons of diesel and about 8 gallons of lubricating oil. Fuel consumption is about 8 miles per gallon, and exhaust filters are run 24 hours without cleaning.

The running time is made up thus: time taken for locomotive to switch from empty to full load at Bankhead, about 75 sec. ; running from First Bankhead to shaft, about 650 yards, with full load, 4 min ; switching from full to empty set at shaft switches, 53 yards, 45 sec.; running empty set from shaft to Bankhead, 5 min ; total time, 11 min. As there are two locomotives running, each one can run four empty sets inbye and run out four full sets, making a total of eight sets per hour and giving a total per shift of 56 sets in and out.

The bankheads are fitted with tub arresters of the screw type made at the colliery, so that, by holding the last tub, the locomotive is able to start with the couplings in tension; it also acts as an addition to braking power over the first hundred feet of the full-tub run. No braking tests on full load and down grade have been recorded.

The economy chiefly aimed at in the changeover from haulage to locomotives was in manpower. Previously, the pit wrought three coal-drawing shifts with stonework distributed over all three. The Output of 1,400 tons was made up of 500 on day and on backshift, and 400 on night shift. With locomotives and the consequent quicker turn round of tubs, coal working was reduced to two shifts drawing 700 tons each, and all stonework done on the night shift.

Drawings and Photographs accompanying the article