990

THE COLLIERY GUARDIAN.

May 26, 1916.

rounded by a water jacket in circulating connection
with a water tank. The pump is insusceptible to the
action of hot air or to any particles of glowing ashes,
etc., which may escape deposition in the drums, this
having been demonstrated with hot coarse ashes at a
temperature of 300-400 degs. Cent.

The following table shows the quantities of small eoal,
not ashes, etc., that can be transported, for the distances
specified, by a suction device of this kind, at an expendi-
ture of 1 horse-power

Distance.	Nut coal. Hot ashes.		Brown coal.	Dust.
Yards.	Kilogs.	Kilogs.	Yards.	Kilogs.
20-100	...	480	240	360	...	180
100-200	400	.	200	300	...	150
200-300	...	281	..	140	210	...	10 i
300-350	220	110	160	...	80

SCHOFIELD SAFETY DEVICE FOR
PIT CAGES.

The safety appliance shown in the accompanying illus-
trations, for suspending pit and similar lift cages, has
been devised by Mr. G. H. Schofield, of Leigh, Lanca-
shire, and is intended to come into operation in the event
of the rope breaking or drawing out at the capping, or
of the detaching hook failing to act.

The lifting hook, attached to the supporting rope or
cable of the cage, passes through a plate, and is con-
nected by a shackle to safety chains, which in turn are
connected to the cage. A number of arms are pivoted
to the plate, and are provided at their outer ends with
sleeves, which slide over the cage guides, such as the
ropes shown in the figures, whilst the inner ends of
these arms are connected to chains which are secured to
the cage.

When the cage is running normally, the tension of
the winding rope on the cage shackle is transmitted to
the plate, and through this to the inner ends of the

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arms (which thereby bear against the plate) and to the
chains connected thereto. This is the position shown in
fig, 1, The arms being held at right angles, the sleeves
do not grip the guides. Fig. 2 shows the position of the
device when the cage is at rest on the catches or keps.
The chains now being slack, the suspender does not
interfere with or impede the progress of changing decks,
and the device, can be lowered on to the top of the cage
for inspection, if desired, without getting out of order.,
so long as the winding rope remains attached.

In the event of the rope becoming detached while the
cage is in motion, the device assumes the position shown
in fig. 3, the weight of the cage then putting tension on
the short chains attached to the inner ends- of the arms,
and thus causing the outer ends of the arms to move
upward, and the sleeves to grip the guides, here shown
as ropes or rods, with the result that the cage'is brought
to a standstill.

Since the operation of the device is effected solely by
the weight of the cage, there is no need for counter-
weights, springs, or the like; and the position of the
suspender above the cage gives a longer bearing to the
latter, thus ensuring greater steadiness in winding.

A project is oil foot in the Isle of Man for utilising the
labour of prisoners of war interned in the island for cutting
and drying peat, with which the island abounds. The scheme
has the approval of the Manx Government officials, but is
being financed privately. In view of the increasing price of
coal, there is every prospect that there will be a considerable
demand from Manx people for peat as fuel. There are many
thousands of acres of mountain and bogland in the island
from which abundant supplies of excellent peat are
procurable.

A HEAVY FREIGHT ELECTRIC
POWER RAILWAY.

By F. C. Coleman.

The North-Eastern Railway Company was one of the
first main line British railway -companies to adopt elec-
tric traction, having, as far back as 1904, when Sir
George Gibb was general manager, successfully applied
electrical operation to the Newcastle and Tyneside
suburban traffic. Once more this company has acted as
a pioneer of electric traction in applying it to heavy
freight haulage.

In 1911, the general manager, Sir A. Kaye Butter-
worth, instructed their consulting electrical engineers,
Messrs. Merz and McLellan, of Westminster and New-
castle-upon-Tyne, to report generally on the question of
electrification with reference to the special conditions of
the North-Eastern system, and, following the visit of
their chief mechanical engineer, Mr. Vincent. Raven,
with Mr. Merz, to the United States in 1911, the
directors decided to proceed at once with a preliminary
scheme.

Electric working was started on July 1, 1915, on the
Shildon—Newport line, a limited service being run in
the first instance, as the overhead track equipment was
not then completed. The service was gradually
extended, until now the full service is virtually in
operation.

Selection of Route.

The Shildon—Newport route was selected for trial,
this being an important. freight line dealing almost
exclusively with heavy mineral traffic.

Some historical interest attaches to this selection,
since the track runs over a portion of the original
Stockton to Darlington Railway, the first public rail-
way on which steam locomotives were used for convey-
ing passengers and goods. The circumstance that the







first trial of heavy freight haulage on a large scale in
England should be carried out on this particular route
is noteworthy.

Power Supply.

Beyond the usual considerations affecting the decision
to apply electric traction to such a line, there was a
special factor which differentiated the North-Eastern
Railway lines from others in the United Kingdom. As
is well known, the production and distribution of elec-
tric power has been developed upon a larger scale on the
north-east coast than in any other part of this country,
and a large proportion of the power is derived from
electric generating stations using as fuel the waste heat
and gases derived from coke ovens and blast furnaces
in the Durham and the Cleveland districts. An ample
supply of cheap electrical energy was therefore avail-
able from the systems of the existing power companies,
and this fact, obviating as it does the necessity for a
large capital expenditure by the railway company on
power station plant, had an important bearing on the
whole scheme.

General Description.

The electrified line has a route length of between 18
and 19 miles, and connects the mineral sidings at
Shildon, which form one of the largest marshalling
yards in Great Britain, with the Erimus sidings at New-
port, near Middlesbrough. A considerable portion of
the sidings at both ends is also electrified, so that,
including the sidings, about 50 miles of single track are
equipped for electric working.

The general gradient is in favour of the laden traffic,
the steepest gradient being 1 in 103. The line carries
the heavy mineral traffic from the South-West Durham
eoal fields to the Middlesbrough district, supplying the
large number of blast furnaces and iron works concen-

trated there. On the return journey, the load consists
mainly of empty-wagons returned to Shildon sidings.

Overhead Track Equipment.

The line is operated on the high-tension direct-current
system, current being supplied to the locomotives
through overhead contact wires at a pressure of 1,500
volts from two rotary converter sub-stations. The over-
head track equipment was carried out under the super-
vision of the railway company’s then chief engineer,
Mr. C. A. Harrison, of Newcastle-upon-Tyne.

The overhead - contact wires on the main port ions of
the track consist of two hard-drawn copper conductors,
each 0-155 sq. in. section, but on certain portions of the
sidings, where the loads are not so heavy, a single con-
tact wire only is used.

The wires are supported by a solid steel auxiliary
catenary wire, by sliding clips. This auxiliary catenary
is in turn suspended from the main stranded steel
catenary by means of steel wire droppers. The main
steel catenary wire is supported from the steel struc-
tures by means of special insulators, double insulation
being used throughout.

The normal span between the steel structures is 110
yards, but on curves and sidings they are placed at lesser
intervals, depending on the conditions existing. The
normal height of the contact wire -from rail level is
16 ft. 6 in., but at level crossings this is increased to
18 ft. 6 in., and under some of the low bridges, of which
there are a large number on this route, the height from
the rail level is reduced, the minimum height being
about 13 ft. 8 in.

Two auxiliary stranded copper feeder wires, each of
0 194 sq. in. section, are carried on the top of the steel
structures referred to, and are connected in parallel
with the main contact wires at frequent intervals.

Each steel structure carries a pair of insulated steady-
ing arms, which are pivoted in all directions, and are
attached to the contact wires by means of clips, their
purpose being to fix the position of the contact wire
relatively to the track. The contact wires are staggered
in the usual way, to prevent undue wearing of the bow-
collectors.

The general type of steel structure consists of two
steel masts and a cross girder, each of these being made
up of two channels, with flat steel bracing. On curves,
a centre strut, steadied by steel tie rods, is added, the
steadying arm on the mast on the inside of the curve
being removed and fixed to the centre strut mentioned,
so as to ensure the steadying arm being always in
tension.

All-steel structures, carrying the overhead track equip-
ment, are bonded to the running rails by means of a
hard copper bond of 0-08 sq. in. section. Any steel
structures carrying signals, and situated in proximity to
the electrical equipment, are also similarly bonded, to
the running rails.

In order to limit, as far as possible, the sag of the
contact wires, due to temperature variation, automatic
tensioning was adopted. The tensioning points are
approximately 1,100 yds. apart.

The tensioning structures consist of strong steel masts
made up of four angle irons, with angle iron bracing,
and are fitted with two cross girders, with a centre strut.
The tensioning weights are slung in the centre of the
mast structure by chains passing over pulleys attached
to the contact wire. A normal tension of about one ton
is maintained by this means in the double contact wire.

On some of the sidings, where only shunting work is
done, and the loads on the locomotives are not heavy, a
single contact wire is used over each track, with ordi-
nary tramway span wire construction.

Terminal Arrangements.

At certain of the marshalling and'reception sidings,
which are not equipped throughout, and on which it is
only necessary for the overhead construction to permit
of the locomotives entering to pick up their load, the
wires are terminated in such a way that if the locomo-
tives should overrun the danger boards, no damage
would be done to the bow- collectors or to the overhead
track.

Section Switches.

The track is sectioned on the normal length at
intervals of about 21 miles, and considerably more
frequently on sidings. Section points are arranged to
occur in most cases at tensioning points, so as to avoid
the use of section insulators. The switches are fitted
with horn break arrangement. They are erected on the
uppermost cross girder of the. section structures, and
operated by levers in the signal cabin, to which they
are connected by the usual arrangement of railway
point rods.

As the train control system of working is in use on
this route, the signal cabins are connected by telephone
with a central control office, situated at Newport, and
the handling of these switches is directed from the same
point.

Bonds.

The track rails are bonded at the joints with stranded
copper bonds fitted under the fish plates, two bonds,
each of 0-109 sq. in. section, being fixed at each joint.
They are also cross-bonded between the two rails at
intervals of 300 ft., and between the two inner rails of
adjacent tracks at the same space interval, the bonds in
the 6 ft. way being mid-way between those in the 4 ft.
way.

Sub-Stations.

There are two rotary converter sub-stations (at.
Aycliffe and Erimus), converting the three-phase high-
tension current as received from the power companies’
system to direct current at 1,500 volts for the over-
head track.

The Aycliffe sub-station contains two 800 kw. rotary
sets, each set consisting of two 400 kw. rotary converters
in series. The Erimus sub-station is generally similar,