General
From diagrams Nos. 1 and 2 the probability may be gathered that formidable transport problems would be presented to the four Union Forces that were to operate on exterior lines.
The ocean transport from Cape Town to Walvis Bay was 850 miles and from Cape Town to Luderitz Bay was 550 miles.
In the enemy territory 1040 miles of railway was repaired and used while 340 miles of new line was laid, partly in Union and partly in enemy territory.
Supplies, with the exception of meat, were unobtainable in the country and the great scarcity of water presented obstacles the elimination of which will be considered in the chapter on engineering.

The Northern Force
The base of this force was Cape Town where dock and embarking facilities were to be had. Walvis Bay, the disembarking end of the 850 miles sea transport line, is sheltered and calm but boats have to anchor about two thousand yards from shore and there are no harbour works. The men, horses and other material, including entire locomotives, were landed on pontoons with from 10 to 50 ton load capacity. The landing jetties were constructed by various types to allow for tide differences (see Chapter Engineering).
A 3 ft 6 in gauge railway was constructed to Swakopmund and the relaying on a 3 ft 6 in gauge of the German 2 ft gauge line from Swakop to Karibib was commenced.
The transport problem of urgent interest however was how to maintain the far advanced and rapidly operating Mounted Field troops, there being absolutely no grazing of any description until Karibib was reached.
After General Botha had cleared the country as far as Goanikontes and Heigamchab (See Tactical Operations) depots were established at these places and at Husab which was in the “No mans land” between the outpost lines at first but later was incorporated under an infantry garrison. By motor lorry and mule wagon trains these intermediate depots were stoked and supplied so that the mounted brigades could rapidly cross the intervening country without transport and only take transport from Husab where a five day supply had been accumulated. After the occupation of Riet, the same method was followed for the advance on Karibib.
This rather novel way of supplying an army in the field by withdrawing the majority of the troops to the base, establishing intermediate depots, and a well stocked advanced depot near the outpost line, and then rushing the troops without transport but maintained by the intermediate “catering establishments” to the advanced depot where they pick up transport with supplies for several days, is not without tactical interest. On a first consideration it may even be classed as a twisting of fortunes caudal appendage that met with more success than it deserved. The probability of enemy interference was however constantly kept in view, and the picked infantry garrisons were well aware of their responsibility of holding an enemy attack until reinforcements could be rushed up. The absence of enemy interference does not constitute any lack of enterprise, he had to consider similar transport difficulties imposed by the desert, and preferred to keep his troops fresh for disputing well selected localities, to frittering them away on missions where the best success would merely have meant delaying the Union advance. As with the strategical innovations connected with the final objective, the best argument as to the propriety of the methods employed, is their success and the consciousness of no other alternative that presented a hope of attaining the desired result.
At the time of the advance on Karibib from Riet, a birds eye view of the Transport and Lines of Communication situation would have shown (Diagram No.5 a) two diverging lines of communication from the base Swakop. The one going to Riet as advanced depot and having intermediate depots to feed large bodies of passing troops, and the other along the railway to Trekkopies. This last being prepared in advance to serve as the main line of communication when Karibib is reached.
On the occupation of Karibib, there was an acute shortage of supplies as the transport had to be switched from the one line of communication on to the other. The advanced base of supplies was made at Usakos (diagram 5 a) the railway being completed to a few miles beyond Trekkopies, from where about fifty miles of rough, sandy country, very unsuitable for motor transport, intervened to Karibib where the field troops now had to be supplied.
The light railway laid by the enemy from Karibib to Pforte could not be made of much service for want of rolling stock, and all efforts were directed to continuing the 3ft 6in line from Trekkoppies to Karibib. This railway was completed to Usakos on the 14th of May but the scarcity of rolling stock, especially locomotives, caused considerable delay before sufficient supplies were accumulated for the final advance.
For this advance (see diagram No.6) one hundred wagons (twelve mules each) was allotted to each Brigade, Brigade Commanders being made responsible for the supply of their own units and the protection of their trains, the lines of communication for each detached force being more or less directly behind its own advance, The main line of of communication was from Walvis to Karibib, under Brig.General Skinner as General Officer Commanding Lines of Communication, was to extend northwards along the railway as rapidly as the enemy demolitions could be repaired and would continually endeavour to shorten the independent lines of communication established by the brigade Commanders. Only mealie meal, coffee, tea, sugar, salt, biscuits, soap, tobacco and matches were carried for issue, meat was to be procured from the country covered in the advance, and the horses and transport mules were to depend on grazing, it was however later found possible to provide the animals with a small grain ration. The railway from Karibib northwards was however on a two feet gauge, and considerable delay would have resulted for want of rolling stock for this gauge if once the advance was seriously checked and the supply carried by each brigade on its hundred wagons exhausted. This danger was only removed when Brig.General Myburghs troops captured the entire rolling stock of this line intact at Tsumeb were all the locomotives stood ready charged and primed for demolition.

Eastern Force
This force with its base at Kimberly, had a line of Communication more than 500 miles long with waterless stretches of more than a hundred miles. The transport was by motor vehicules and mule wagons. On the long waterless stretches tank stations wers established that were filled with motor cars carrying 60 gallons each, these cars of which about 40 were alloted to each tank station, worked in pairs,the drivers having to fill and empty the drums themselves.

Central Force
The transport of this force was by sea from Cape Town to Luderitz Bay, there were however better disembarking facilities than at Walvis Bay as the jetty and cranes of the port were soon repaired. Water was however very scarce and had to be condensed from sea water (see chapter Engineering). The three feet 6 inch gauge railway to Keetmanshoop was repaired as far as Aus where General MacKenzie began to build up a supply depot for his further advance, he had about a hundred wagons available and with these he commenced the advance on Gibeon. This wagon train sufficed for the supply of his troops near Gibeon until the railway was repaired.

Southern Force
This was partly based in Uppington to where a railway had been constructed from Prieska, and partly on Steinkopff. The troops at Steinkopff were supplied by an ocean line from Cape Town to Port Nolloth and thence by the Cape Copper Companies railway to Steinkopff. The railway from Prieska to Uppington was extended behind the advancing troops until it joined the enemy railway system at Kalkfontein. The Field Troops being supplied from railhead by mule wagon supply columns.