The principal difficulty which besets the engineer is the system of pipes, etc., very often complicated, which come to view on opening up the ground, which in all cases have to be diverted. The unfortunate part is that, however accurate the borough surveyors' maps are, the depth of small water and gas mains is rarely obtainable; hence, estimating is very difficult. It is stated on reliable authority that the cost of this system for double track lies between

£26,000 and £32,000 per mile. It may be mentioned, also, that side slots are also used, but find disfavour by some, because the slot has to be large

3/2

214"

FIG. 1062.

enough for the wheel flange to run in, causing a considerable gap on the points, which are very dangerous. This has led to a combined system-side-slot on straight lines and centre-slot for points.

Fig. 1061 shows the London County Council system, which is fairly typical, and the soft-steel conductor rails in fig. 1062. The conduits want very careful draining. On gradients this is obviously easy; on the straight, however, sumps are sunk every 120 ft. or so, the conduits falling both ways.

The surface-contact system is little used in England, at the time of writing Wolverhampton being the only city to adopt it. Briefly, the system consists of studs on the roadway, about 3 in. in diameter, placed at 10-16 ft. centres, and projecting when in action about half an inch. The distance apart will, of course, be limited by the smallest cars used.

For description, the writer has chosen the Lorraine system, as being of greatest interest to British engineers, being in working at Wolverhamp ton. The two outer skates are magnetised, while the centre one, made of phosphor bronze, is suspended from a wooden bar by means of a piece of

rubber. It will be seen from fig. 1063 that the cast-iron studs have nickelsteel centres: when the skate passes over the stud, the lower carbon contact

and the armature are raised; thus connection with the upper contact is made.

APPENDICES.

APPENDIX I.

A VERY frequent duty of the civil engineer, especially those who serve public bodies, is the preparation of plans of work to be sanctioned by Parliament or the Local Government Board, the latter principally in the case of loans repayable over a certain number of years. Like similar engineering matters, there is much law to be considered; and although an engineer certainly benefits by reason of having a sound knowledge of legal matters, this being a book on Engineering, we have avoided altogether legal aspects, though there is a great temptation to include them. The following are the general requirements of the Local Government Board.

Elevations, plans, and sections of structural works should be on a scale of not more than 8 ft. to 1 in. The scale of the general plans should be the same as the horizontal scale of the sections, and the vertical scale of sections of sewers should be of not more than 10 ft. to 1 in. Copies of drawings and plans on tracing-linen are preferable to copies on paper. When it is practicable, plans and tracings are much more conveniently transmitted folded than in a roll.

Specifications should contain clauses as to payments and retention money; term of completion of work; penalty for default; extras and alterations (orders for which should, in all cases, be specified to be made by the Council); subletting; annulling of contract for insufficient progress; responsibility of contractor for damages by trespass or otherwise; term of maintenance; and settlement of disputes.

In the case of laying pipes or sewers, inspection and testing previous to the work being covered up should be provided for.

In the case of cast-iron pipes under pressure, the specification should require that they should be actually tested. The weight of pipes is best specified by stating the weight of a pipe-length (in the work) for each size.

Cement should be subject to specified tests for strength, fineness, and weight.

The joints of pipe sewers should be made with cement mortar, and the specification should provide for thoroughly clearing the pipes after jointing.

REGULATIONS FOR SEWERAGE WORKS.

I. A map of the district to be sewered, on a scale of not more than 220 ft. to 1 in., showing the dimensions and course of all proposed sewers, positions of manholes, ventilators, and gully-traps, the inclination of each sewer or pipe sewer from point to point, and the heights at each of such points of the surface of the streets, and of the lowest interior part of the sewer or pipe sewer, both expressed in feet and decimals, over a fixed common reference datum point, referred to Ordnance datum.

II. The course, dimensions, and levels of existing sewers, and information as to how they are to be dealt with.

III. In case of a discharge into tidal waters being proposed, a map of the district adjoining the outfall, corrected to date as to new buildings. The lines and levels of

high and low water, springs and neaps, should be shown, and any information available as to outside soundings and currents should be given.

N.B.-The consent of the Board of Trade must be obtained to the execution of any works below high-water mark.

IV. A statement of the area contributing to each outfall, with its population. V. Any special duties likely to be thrown on the sewers from factories. VI. Is there a probability of a neighbouring district seeking the use of the proposed sewers? Full particulars as to area, population, etc., are to be given.

VII. Are any portions of the proposed works to be situate outside the district? VIII. In what manner and where the sewage is to be disposed of, having regard to the provisions of the 19th section of the P. H. Act 1878, which forbids any authority to make or use any sewer, drain, or outfall for the purpose of conveying sewage or filthy water into any natural stream or watercourse, or into any canal, pond, or lake until such sewage or filthy water is freed from all excrementitious matter, or other foul or noxious matter, such as would affect or deteriorate the purity in such stream or watercourse, or in such canal, pond, or lake, also observing the provisions of the Rivers Pollution Prevention Act, 1876, 39 and 40 Vict. cap. 75.

SPECIAL REGULATIONS FOR WATERWORKS.

I. The number of inhabitants in the district it is proposed to supply with water. II. The source from which the water is to be taken and the quantity it will supply, with the method by which such quantity has been ascertained.

III. The working head in ft. over the highest point to be supplied in the district. IV. A copy of the analysis of the water. (An analysis must be obtained in each case.)

V. The quantity of water which it is proposed to supply daily for drinking and domestic purposes.

VI. The quantities to be supplied for other purposes, specifying same.

VII. An Ordnance map, on the scale of 6 in. to 1 mile, showing the source, position of the works, the catchment area, and the course of the mains.

VIII. A longitudinal section along track of supply main, referred to Ordnance datum.

IX. A map of the district to be supplied on a scale of not more than 220 ft. to 1 in., showing the position and diameter of distributing pipes, positions of fountains, and a sufficient number of heights of the surfaces of the streets over Ordnance datum, to enable a judgment to be formed of the efficiency of the scheme. If any existing pipe-supply is in use, the works and pipes thereof should be shown.

X. If the district is supplied by any water company, full particulars should be given of the constitution and rights of the company, and the supply afforded by them. XI. Any available information as to rainfall or gaugings.

XII. Whether the right to take the water has been secured, both as regards (1) the owners and occupiers of land where the supply is taken off, and (2) the riparian owners or occupiers below that point.

XIII. The storage capacity of any reservoir or service tank.

XIV. Are any portions of the proposed works to be situate outside the district? XV. Any further particulars bearing on the case.

APPENDIX II.

A VERY important duty of an engineer, after designing his works, getting out the quantities, and finally advertising his tenders, is to see that the conditions under which such contract is to be executed are properly drawn up. It is also equally essential that the proper forms of tender be drawn up; and to aid the proper drawing up of such documents when left to the engineer, the writer has added examples of the conditions and forms referred to which have been in use in his office for many years. They can, of course, be altered, abridged, and amplified to suit special cases.

Two shorter forms of tender for small jobs are also given, A and B.

GENERAL CONDITIONS OF CONTRACT.

INDEX.

As to-Plans, Specification, Copies thereof, and their Custody
Conformity with Plans and Specification.

Plant, and Employer's Temporary Property therein
Setting out Work, and Responsibility for Errors
Materials, Property therein when delivered

Protection of Works from Weather-Suspension of same.
Completion of Works

Defective Materials and Workmanship, etc.

Deviations, Omissions, Variations

Clerk of Works

Engineer's Control and Judgment

Engineer's Decision

Payments.

Responsibility for Damages

Bankruptcy

Employer's Right of Access

Provision of Sums in Specification

Adjoining Buildings

Subletting

Plans, specifications,

copies there

NOTE. In the following Conditions and Specification of Works, the term "the Employer" is to be held to designate the one party in this contract, viz. for whom the work is to be executed; and the term "the Contractor" is to be held to designate the other party to the contract, viz. by whom the works are to be executed.

The term "the Engineer" shall, in the case of death or inability from any cause of the Engineer whose name is subscribed to the plans and specification, be held to designate one of the following, viz.

or

,

or

whom the Employer shall appoint in such case to carry into effect the provisions of the contract; or in case of the inability or failure of such Engineer, then such Engineer (being a Member of the Institute of Civil Engineers) as the Employer shall appoint.

1. One set of copies of the Contract Drawings and Specification, together with such further drawings as may be from time to time required in the further elucidation of, and their thereof, shall be provided by the Engineer to the Contractor for his own use, and the same, or copies thereof, are to be kept on the buildings in charge of a competent foreman, who is to be constantly kept on the ground by the Contractor, and to whom instructions can be given by the Engineer.

custody.

Conformity

and specification.

The Contractor to make all copies, other than those above described, that he may require for his own use, of either drawings, specification, or details: and all copies must be returned to the Engineer before the final certificate is given, and the Contractor shall not be entitled to require such certificate until all said copies shall have been delivered up, or their loss accounted for to the satisfaction of the Engineer. The Contract Drawings are to be signed by the Engineer and Contractor, and the whole of the works are to be executed in all respects in conformity therewith, and also with such further drawings and instructions as may be hereafter provided for the elucidation thereof.

2. Any descriptions or particulars written on the drawings are to be equally with plans binding as if contained in the specification, and everything is to be done that is usual and necessary for the completion of the several works comprehending what may be reasonably implied by or inferred from the drawings or specification, although the same may not be specially mentioned.

Should there appear on the face of the drawings any works not described in the specification, or should there be any works described in the specification and not shown on the drawings, they shall be respectively taken as if described and shown in