The trench system on the Western Front consisted of front-line, support and reserve trenches. The three rows of trenches covered between 200 and 500 yards of ground. Communication trenches were dug at an angle to those facing the enemy. These trenches used to transport men, equipment and food supplies.
The French tended to use tramways whereas Britain relied on their soldiers to carry supplies to forward positions. These carrying parties took supplies of water, food, ammunition, bombs and trench stores to the front-line. The communication trench was also used to transport wounded men to Casualty Clearing Station. Sometimes communication trenches were partly traversed and fire-stepped in case the enemy managed to break-through the front-line.
The communication trench was just wide enough to accommodate a man with a full-pack, and about seven feet deep, so that one's vision was limited to a patch of darkening sky and the shoulders of the man in front. Its floor was covered with a foot of tensely glutinous mud. We drove slowly through the morass, wrenching out each foot before putting it down again.
Darkness fell. After what seemed half a night, the guide stopped and said: "There's a road here. See and hurry over it. There's a machine gun on it. See? One at a time."
We tore ourselves singly from the mud and bundled on to the road, diving towards a dark opening in the other bank. The machine gun threw a few desultory shots past us. The bullets cracked sharply overhead. We tumbled into another trench and went on. This one was narrow, too, but shallower and duck-boarded. We moved more quickly. We could see lights raising and falling in front of us, and the noises interpreted themselves as rifles and machine guns firing.
Suddenly someone said: "Hullo," and Smith, my company commander, loomed up. "Is this the front line? I asked. "That's it."
At all points subject to shell fire access to the firing line from behind is provided by communication trenches. These are now so good that it is possible to cross in safety the fire-swept zone to the advanced trenches from the billets in villages, the bivouacs in quarries, or the other places where the headquarters of units happen to be.
We move off, marching to attention until clear of the town, not a man out of step though they are all carrying an enormous amount of kit, wood, charcoal, etc., every rifle properly sloped, every man looking to his front. A sergeant shouts, 'Hold your head up, Brown, you're not fit to be a blank highlander, put him in the report Idle Marching.' The time by the way is about six o'clock, the light rapidly going. Then out on to the famous high road Bethune-La Bassee. Absolutely straight with trees on both sides and pave underfoot. About four miles of this and then we reach Brigade Headquarters, the beginning of the danger zone. The houses are shattered here on both sides of the road and a few bullets sigh over head and a few strike sparks from the pave. A man is hit and the stretchers bear him away. Two shells then, not far off and most unpleasant as we are in column of fours. However no damages done. It is now moonlight and we turn off the main road, forming single file, the light showing up one side of the men very clearly and making their waterproof sheets glisten, and leaving the other in deep shadow. More bullets along this lane though all over our heads. These are all stray shots as we are out of sight of the enemy, as indeed we have been all along. Under the shadow of a building without a roof, but otherwise undamaged (used as a dressing station).
We turn into Hertford Street, the communication trench dug by the Hertford Territorials during the day, when there are only very occasional stray bullets about this area. Walking up a communication trench behind a lot of men is a beastly business. The trench is very muddy, and where the parapet is low and the bullets are coming two a minute (though high, mark you) you may bet the line is held up for a few seconds. This goes on for about three parts of a mile, and then we reach some farm buildings, the walls riddled with shell-holes, which make little irregular pools of moonlight on the floors as we file rapidly through; on again, skirting a big barn, without a tile on the roof, and the woodwork fined down by bullets and the moonlight, into a wonderful grey, gauze-like tracery. This barn has kept its dignity, unlike the other broken buildings that have all lost their self-respect.
We go in to the trenches for four days, while the weather becomes atrocious. It is notorious that French trenches are seldom good and these are no exceptions. Because there is no revetting, walls of fire and communication trenches fall in, so-called dugouts collapse, and telephone wires connecting companies and brigade become non-effective, consequent on the landslide. The men are up to their waists in mud and water. Rats drown and rations cannot be got up.