166 SECTIONAL ADDRESSES. 



will be supplied, from electrical systems, the equivalent output would be 

 19,000,000,000 units per annum. 



Now we know that the usual ratio of plant connected to electrical 

 systems to the maximum load is 2.5 : 1, that the average industrial load 

 factor is about 30 per cent., having regard to the variety of trades — the 

 output from public generating stations for industrial power in 1924-.5 

 was 3,556,000,000 units, and the rate of growth has been in recent years 

 25 per cent, per annum. 



From all these data it may be fairly assumed that if the majority of 

 our industrial works (omitting certain classes which require steam for 

 particular processes) derived their supply from public systems of supply, 

 and an increasing use of power per employee must also be assumed, we 

 should expect a future output for industrial power of not less than 

 20,000,000,000 units with a maximum load of 9,200,000 kilowatts. There 

 are certain well-equipped collieries which will probably continue to retain 

 their own plant by reason of their high load factor, and the cheap small 

 fuel which they consume with a consequent low cost of production. The 

 large output from these collieries cannot be credited to the future output 

 from public systems of supply. 



There are possibilities of great expansion in railway electrification in 

 this country. The present electrified systems, with the exception of the 

 Shildon Branch Line in the County of Durham, are confined to suburban 

 services. The largest development is that of the Southern Railway 

 (Metropolitan Suburban) lines ; the others being the London Electric 

 Railways, the Metropolitan District Railway, London and North Eastern 

 Railway (Tyneside), and the London Midland and Scottish Watford line, 

 Lancaster-Heysham Branch, Liverpool Southport and Manchester-Bury 

 systems. The present output for railway traction is about 700,000,000 

 units, 615,000,000 units of which are generated at stations belonging to 

 the railway companies, the remainder being purchased from general 

 supply systems. A Committee of the Ministry of Transport reported 

 within the last few years the desirability of standardising railway electrical 

 systems so far as is practicable, having regard to what has already been 

 put into operation. That Committee recommended that the supply for 

 traction purposes should be generated in the form of 3-phase 50-cycle 

 energy, and converted in the requisite sub -stations to direct current with 

 a conductor pressure of 1,500 volts or a multiple (or sub-multiple) of 

 that pressure. The Inner London systems have already adopted 600 

 volts D.C. extensively, and cannot be reconciled comj^letely with a 

 pressure of 750 volts, which would be the practical sub-multiple of the 

 recommended standard. In the case of the A.C. 11,000-volt system — - 

 twenty-five cycles — in operation on that part of the Southern Suburban 

 services originally known as the L.B. & S.C., a recent public statement of 

 the chairman of that railway made it clear that a change to the D.C. 

 system is being contemplated. In France the Government have adopted 

 a standard of 1,500 volts D.C, and extensive systems in the Midi are now 

 being electrified ; other French railway systems will also be converted from 

 steam to electric traction. In a recent report published by the British 

 Government it was stated that calculations had been made by the 

 Ministry of Transport of the total consumption by British railways were 



