288 SOME SIUNICIPAL ENGINEEEING PROBLEMS IN THE TROPICS 



Tramways The permanent way of tramways is now such an integral part of street-making that 



some reference might be made to the system in vogue at Khartoum. The tramway here is 

 in reality a light railway of '60 metre gauge, consisting of flat-bottomed rails weighing 

 12 kilos per lineal metre, laid on steel sleepers. It does not run in the metalled parts of the 

 streets, but where this is unavoidable, as at crossings, guard rails are provided to preserve 

 the flangeway. Tramway section rails are also in use at crossings and on curves, but these 

 are not satisfactory unless some causewaying is done both outside and inside the rail. 

 The photograph (Fig. 81) shows the Khartoum Central Station and the type of rolling 

 stock in use. 

 Open spaces The provision of a certain amount of open space, while improving the amenity is also 



very desirable on hygienic grounds, especially in the more densely populated native and 

 business portions of a town. 



Eeference to the plan (Fig. 84) will show that in the hrst class quarter iu Khartoum 

 there are public gardens at the Gordon Statue in Khedive Avenue, while at the west end 

 of the town there are the Zoological Gardens. The photograph (Fig. 80) shows the 

 public gardens with the Gordon Statue at the crossing of the avenues and the Palace 

 in the background. 



The most important open space, however, is Abbas Square between the second and 

 third class quarters, which is 800 yards long and 200 yards wide. Meantime this square 

 is only partly laid out, but the complete scheme is indicated on the plan (Fig. 84). 



In the third class quarter there is the native market, to a large extent simply an open 

 space, in which the merchandise, consisting principally of grain and fire-wood, is laid out. 



The provision of future open spaces in Khartoum has already been referred to. 

 Trees Trees, which are planted in double rows in the avenues and single rows in the streets, 



besides providing very desirable shade and improving the amenity, do much to protect 

 the street surfaces and allay the dust nuisance. The following information on tree 

 planting in Khartoum has been kindly provided by the Superintendent of Public Gardens, 

 Mr. F. S. Sillitoe. 



There are now in the avenues and streets from .3000 to 4000 trees of the following 

 varieties : — 



Albizzia lebbek (Lebbek) is a well-known tree tliroughout Egypt. It is deciduous, 

 which is a great drawback as it is bare during a part of the winter, but it soon bursts into 

 new growth of a beautiful green colour and its flowers have a delicious perfume. Seed is 

 produced abundantly, in long pods, which, when ripe, it is advisable to remove as they give 

 the tree an untidy appearance. 



Albizzia procera, a native of India, is a quicker-growing tree than the former, but is 

 useless unless it has good soil and f)lenty of water. 



Fious bengalensis (Banyan), also a native of India, is well known on account of its serial 

 roots, which in this dry climate have scarcely appeared as yet on nine-year-old trees. 

 This is the best of all trees here, but it should not be planted beside buildings, especially if 

 near water, as the roots are so strong and penetrative. The large roots that spring from 

 the base of old trees are also apt to cause inconvenience iu the footpaths. The foliage is 

 of a bright colour, and nearly evergreen. 



Ficus sycamorus (Gameza) is also a fine shade tree but is of a much duller colour. 



Ficus religiosa, with the peculiar long apex to its leaf, has also been tried and found 

 satisfactory. 



Kigeiia xthiopica (" Sausage tree," on account of its large seed pods which hang on 

 long stems) is a native of tropical Africa, and has proved a fine shade tree if given plenty 



