Preliminary Report on Adelaide and Burra Railway, from Gawler Town, Northwards.
Norwood, July 31st, 1854.
Sir—I have the honour to report that I have completed an examination, for railway purposes, of the country between Gawler Town and the Burra; the district between Adelaide and Gawler Town having been already examined and surveyed by Mr Hamilton, and the plans being in course of preparation (if not finished), I consider it unnecessary to make any observations thereon.
In making a reconnaissance of this nature, as very much time may be expended unprofitably, I endeavoured to ensure as much as possible, by previous careful consideration, that no delay should occur amongst the mountain ranges, which in this country, as distinguished from Europe generally, appear to offer impediments of no ordinary nature, from the valleys being seldom continuous; on the contrary, terminating in most cases, when followed up, by inaccessible ridges rising very abruptly; and the probable unprofitable examination of the valleys one after another, determined me to seek for tracts of country sufficiently away from the hills to be without difficulties of this sort.
I, therefore, naturally turned my attention to any existing rivers and plains in about the direction required, and which from their length were worth while sacrificing any minor considerations to make available for the purpose in view. In carrying out this idea, I have been so far successful as to find no less than three routes between Gawler Town and the Burra, more or less suitable; which, with the assistance of the accompanying map, I shall briefly attempt to describe, recommending to be surveyed the one apparently the most suitable, with the reasons; and afterwards give a general view of what appears to me the most economical method of carrying out the requisite surveys, with a few remarks upon the construction of the works.
The three routes explored will be best understood as the “Gilbert,” the “Kapunda,” and the ” Wakefield” routes.
The first of these I took into consideration from the fact of the River Gilbert running a north and a south course for a distance of about 28 miles; and having satisfied myself, by inspection, of the suitability of its banks, it was next required to arrive at its southern extremity; to do which, at first, no ordinary difficulties presented themselves from the altitude of the hills, north of Willaston; but having ascertained that these hills declined to the westward, by making several excursions through the scrub, in a north-west direction, I have come to the conclusion that the route is practicable to the banks of tha (sic) River Light, about a mile below where the Gilbert effects its junction with the river; that is, continuing Mr Hamilton’s line from Adelaide so as not to cross the Gawler River nearer the town of that name than about two miles and three quarters below it, to avoid expense which would result from passing closer to or through it, and also do away with severe gradients ; going through the scrub in a north-north-west direction, with a few sand hill cuttings of no great moment, and passing from this scrub to a plain, a flat hollow in the latter is taken advantage of, leading by Grant and Butler’s station, and conducts to the River Light not far from where the Gilbert flows into it, near Boylan’s cottage; following up the northern bank of the latter river as far as Ayliffe’s Inn on the North-road, this distance (four miles) would be comparatively expensive from heavy surface formations and side cuttings being required; after which the banks of the Gilbert may be made available for a further distance of about 28 miles up to its source.
At this point, the ground begins to rise rapidly, and passing into the plain west of Tapley’s Inn, cuttings should be undertaken for a depth, of at least 25 feet, and of an aggregate length of, possibly, a furlong, being apparently the engineering difficulty of the route. These cuttings are required where the Rivers Gilbert and Wakefield, with their dividing ranges, take their rise, and would be three in number, the last being through the lowest point of the northernmost range, near where it is crossed by the Kapunda Road, and leading into the aforesaid plain; at these cuttings attention will be required to save expense, and skill shown in planning the route.
The plain arrived at, an easy descending gradient conducts to the Salt Lagoon, where some trifling cuttings and fillings will prevent the west bank being skirted too circuitously ; passing through a gap in the range close by, and pursuing, generally, a northerly course, the neighbourhood of Gum Creek is gained by a gradual ascent.
From Gum Creek the lower part of the hills on the right hand will have to be wound round; which, consisting of alternate rises and watercourses, will occasion some earthwork and culverts; after which, the Burra can be made without difficulty by a short descent and a long ascent afterwards; passing round and leaving close on the east the Copper Works, and continuing along the banks of the Burra Creek into the township.
As there is a considerable rise from Gawler Town to the Burra, although this route appears favourable, it may happen that, notwithstanding the distance (about 75 miles), the gradients may have to be rendered easier by making the route more circuitous ; and the same remark holds good respecting the two other routes explored, and hereafter to be described; and I may fnrther (sic) add that, as regards this line and the others between Gawler and Kooringa, where a route or gradient is considered suitable or the contrary, it is merely an opinion expressed after careful examination, and not a confident assertion of practicability or impracticability, which would be quite irregular without a proper engineering survey.
The first portion of the Gilbert route being carried through scrub and timber, the latter may be made available for cross sleepers for a distance of some 10 or 12 miles. It is probable that stone also may be procured in this locality for ballasting, in some of the hills eastward of this line.
Stone makes its appearance along the banks of the rivers Light and Gilbert; and, besides, ranges of hills where it abounds, exist at no great distance along the course of the River Gilbert, and generally throughout that line.
The next direction taken into consideration was to make available the banks of the River Light in its north and south course, and to do which it appeared desirable to make for the bend in that river where it turns eastward, and in its horseshoe course winds round the township of Kapunda.
In order to reach this bend, it is necessary to gain the hill north of Willaston; and here a difficulty arises. By, however, sweeping round by the Gawler River above the town, this perhaps, might be accomplished; but the gradient would be severe—in this case, the line would be an extension of Mr Hamilton’s from Gawler Town. Another way of overcoming the rise, and probably more successful, might be by the course a. b. This would take up Mr Hamilton’s line south of the Gawler River, and following the lie of the land, sweep round, up one of the existing hollows, crossing the North Road, south of Templar’s Inn. The high ground, when attained, should be preserved, and pursuing, to keep the level, a rather serpentine course through biscay land, a descent to reach the banks of the Light would be required—a steep gradient, perhaps practicable by the route c. d.—in which case considerable skill must be exerted, and two or three deep cuttings for short distances, and large culverts made, in order to get out of the north extremity of the plain, in which is situated the Sheaoak, Log public-house, and getting over the rise, to descend to the river.
Another route would be by c. c., a descent through thick scrub. In either, the works to Ross’s Creek would be very expensive, on account of the lengthy and very tortuous course of the Light, and the rocky and precipitous nature of its banks. The stream here has its bed apparently through the only gorge in the locality by which the hills can be penetrated for railway purposes, a gorge of about two miles length.
Following up Ross’s Creek, difficult gradients with heavy surface forming from side long banks, would be encountered, accompanied by some short and deep cuttings, leading into Allen’s Creek, which being pursued for a short distance, a further cutting of some extent would lead to the desired bend across the Waterloo Plains.
A more circuitous route, with better levels, may be had, with some heavy surface forming, from the Light, by following Allen’s Creek, and leaving it as above to the same bend. It may here be observed, that an elevated viaduct over the Light would help the gradients, approaching that river from the south, as well as leaving it northwards by Ross’s Creek, This, of course, would be expensive.
Following from the bend, the river known here as the “Dirty Light” to where it receives Tothill’s Creek, and continuing the route to the head of the latter, a cutting of about twenty-five feet in depth, for some distance, would lead between the eastern bank of the small lagoon (south-east of Tapley’s Inn) and the adjacent hills, on a good level; and, taking advantage of a gap in the range, conduct by Logan’s Flat to a creek, which followed, leads to another gap in the hills bounding the flat on the east; and so on northwards to a small moor, where the Burra Creek appears to take its rise, leading into which an embankment would have to be made.
This creek is afterwards practicable to Kooringa, along its banks, some short but deep rock cuttings, trifling works, being required.
This route, from Robinson’s Inn to Kooringa, is generally a good one, and its quickest incline and most expensive work apparently at the head of Tothill’s Creek, at the cutting before mentioned; but the remainder, from Robinson’s to Gawler Town, is undesirable, from its steep gradients, and in several places expensive nature; from which reasons it is certainly inferior to the Gilbert line, so far as can be judged from occular examination. Generally, there is no want of stone along this route; between Willaston and the Light it does not however show. Some timber fit for sleepers exists at the head of Tothill’s Creek, near the Smelting Works, probably private property.
In endeavouring to get a line by the Wakefield country, advantage is taken of an extensive plain in the County of Gawler, west of the ranges in which are situated the trigonometrical stations Wakefield and Gilbert.
The Gilbert route would be followed from the Gawler River to the Light, which latter would be crossed at much the same point by following either line.
The aforesaid plain would, with generally good levels for the first few miles, offer a rather quick rise to within about four miles of the Wakefisld (sic); to lessen this rise, ground must be gained at first along the slope of the range eastward.
The summit-level arrived at, a descent to the Wakefield at Salter’s Creek can be made, leaving the mountain ranges close at hand on the right, where they run up to and abut upon that river, the course of which must be followed, as it leads northwards, to obtain a suitable level to the plains north-east of Mintaro.
But the descent by Salter’s Creek would be a doubtful gradient, and the first four miles up the banks of the Wakefield, through the gorges of the mountains, so tortuous and precipitous as to be very expensive, requiring many bridges, and side cutting through three fourths of the way.
The bend of the Wakefield being arrived at, the banks are very favourable, passing northwards by Auburn to Bowman’s sheep station, from which place a creek with steep gradients leads on to an extensive plain, the creek requiring heavy surface formation along its banks. The eastern rauge (sic) of hills descending to this plain will next have to be skirted, and ground gained as much as possible to cross the Wheelbarrow Hills (a work of, perhaps, doubtful practicability, with reference to reasonable expense), which bound another plain to the eastward leading to the Burra, a plain on a much higher level.
The gradient over the Wheelbarrow Hills would undoubtedly be a stiff one. Once crossed, a course much the same as the Gilbert line (which it would run into) appears advisable.
It is to be observed, that, in making a reconnaissance of the country between Gawler and the Burra, the examination of the ground has not beeen (sic) merely confined to the routes reported on, for it was indispensable to travel in many directions to discover these routes, in doing which the features of the lands adjacent to them became known; and if other practicable lines had existed, they would not have escaped observation.
In summing up as to the merits or demerits of the three routes explored between Gawler Town and the Burra, it may not be out of place briefly to recapitulate some of the leading points in those routes requiring consideration.
And, firstly, the Gilbert route is comparatively expensive between the Light and Ayliffe’s Inn, from earthworks of greater or less magnitude being required, also at the cuttings to be undertaken near the head of the Gilbert, and, lastly, at the formation near Gum Creek; but the rest of the route, so far as can be perceived, has good gradients and inexpensive formation, with few bridges, and the difficulties of the line are quite trifling when the length of suitable country is taken into aacount (sic).
Secondly, the Kapunda route is undesirable, from the elevation at first to be attained and afterwards abandoned in making the River Light, the latter proceeding being accompanied with exposure, and both introducing gradients of doubtful character; also the steep ascent by Ross’s Creek, with its accompanying expense, and the reaching that creek by the difficult and serpentine gorge of the Light. Again, the alternative of leaving the latter river by Allen’s Creek, instead of Ross’s is very circuitous ; and the departure from Allen’s Creek (which must also be partly followed near its source, in the event of the adoption of Ross’s Creek), with its necessary cuttings, and steep gradient before crossing the Waterloo Plains, being also taken into account. These works form engineering difficulties, of more or less moment, before any groat distance is reached. Also, from Robinson’s, a cutting of no small cost, at the head of Tothill’s Creek, has to be undertaken; although, with this exception, this portion of the route is compatively (sic) unexceptionable, and any further obstacles are of small account when divided over the remaining portion of the line.
Thirdly, the Wakefield route presents the gradients to be overcome in making the Wakefield from the County of Gawler. The extremely tortuous and very expensive formation required, as well as bridges, in arriving at the bend in this river from the junction with it, and the doubtful character of and certainly stiff gradient in surmounting the Wheelbarrow Hills.
All these things considered, I must certainly declare myself in favour of the Gilbert route, as presenting the longest, and, therefore, in all probability, the best gradients, and being, so far as can be judged, the cheapest line, and perhaps the shortest, though, for this matter, they are all much about the same length.
In order to have the survey conducted with economy, it would be advisable to have flying levels taken at first, and data fixed thereby to assist in determining the gradients, which, between the Light and the rise of the Gilbert, must be managed so as to cross the rises at the latter place with the least cutting possible.
Also, this latter portion of the route ought to be first surveyed, to ensure its practicability with reasonable economy, previous to incurring the expense of surveying the approach to it by the valley of the Gilbert. Should the rise along the river present too steep an incline, means must be taken to lengthen the route in this locality.
In considering the construction of the works, it is advisable to bear in mind that requisites to be procured in Europe or elsewhere may, with advantage, be sent for early, so as to be available when the surveys are completed.
I would recommend the adoption of native timber for sleepers, whenever procurable at reasonable expense; in order to manage with economy, the line may be commenced in places where quarries are at hand, rails laid and taken advantage of in the transport of materials, by which proceeding an extraordinary saving may be effected; also the same system to be carried out in working the cuttings.
A wide guage should not be adopted in making use of native timber, as the latter, when small, does not carry any great length It may be objected that the ravages of the white ants, &c., would quickly destroy sleepers of this kind—but then they will have already done good service in assisting at the formation of the permanent way; and if they are quickly destroyed, which is by no means certain, when bedded on a high and dry foundation of broken stone or similar balasting, they can be replaced from time to time by foreign timber properly prepared; so that it is advisable to have the rails ordered in the outset. The bridge rail, which can be used with longitudinal or transverse sleepers, appears the best, and of such weight as shall be agreed upon after due deliberation on the nature and speed of the future traffic. The sleepers to be transverse when native timber is used (or replaced), and generally longitudinal when foreign timber is introduced.
The route shown in the accompanying map can only be taken as approximations to the actual courses wished to be described; particularly, as when not in the vicinity of rivers, roads, or surveyed land, the country could not be identified with the map, and therefore there was no way of fixing the actual positions so as to lay them down; but the routes are readily recognisable in travelling over the ground—to assist which, copious notes have been taken discriptive (sic) of the localities.
A new feature in railway engineering will perhaps be found in carrying out railways in this country, and that is, that cuttings will often be made without the excavated earth being used in the approaches to same, the reason being the suddenness which valleys terminate in ridges across their upper ends, and the perhaps already quick gradient to those ridges; this must dispense with the practice of making such a passage out from a valley half in cutting and half in embankment, and consequently “putting out the earth to spoil,” as it is termed, will be attended with some additional expense.
All cutch drains ought to be made as narrow, shallow, and with as little fall as will barley suit, to allow for future degradation by the action of running or surface water.
After having taken the levels of the most difficult portion of the Gilbert route, it may be prudent to take trial sections of the corresponding difficulties of one or both of the other routes, to set finally at rest any question as to their comparative merits.
It is stated that about 30 miles to the east of Tapley’s Inn, towards the Murray, there exist a belt of pines, varying from 10 to 40 feet in height, and in considerable quantity. This information I have derived from a Mr John Stanway, of Spring Gardens, near the Burra, who is willing, if called upon, to point them out—they being enclosed by scrub. The knowledge of their existence is important; as, where native timber is used for sleepers, they will be found very convenient, from their straightness and the ease with which they can be cut. The advantages of using native timber has been before touched upon; and I consider that further information respecting the pines should be obtained.
It does not appear that parties competent to take levels are coming forward; and it may be advisable to advertise for such persons in the local as well as the Melbourne newspapers, stating salary, and for what term they will be ensured employment. Measures being thus taken to make pubic that levellers are wanting, will prevent delay in commencing operations The eligibility of parties applying from Victoria should be ascertained before inviting them to take appointments, to prevent any unpleasantness hereafter, should they be found deficient.
I have, &c.,
Chas. T. Hargrave.
The hon, the Colonial Secretary.