various colors, symbols and line types used in the chart may be included in the time–distance diagram. Other information shown may be cost and resource histograms along the time axis. The drawing area may contain grid lines to ease comprehension of the chart: hours, days, weeks, months, years, for the time axis; equidistant units along the distance axis or specific locations (piles, stations, foundations, etc.). The background of the drawing area may be enhanced with time and location related information such as close seasons, hold-off intervals, meteorological data (rain/snow fall, temperatures). The project activities are placed within the drawing area according to their specific nature: Simple activities such as cable pulling, fencing, road surfacing can be drawn as a single line: The work crew starts on a given location at a given time and continues with linear progress. Exhibit 1 shows two such activities: Activity 1 starts in Week 1 on Day 3 from km 0+000 and continues until Week 2, Day 13, progressing until km 1+100. Activity 2 starts the next day at km 2+000 and continues until Day 19 to km 1+100. These two activities could be performed by a single work crew as the second activity starts right after the first. When an activity in a specific area takes a considerable time, the activity would be drawn as a rectangle with the sides of the rectangle corresponding to the length of the work site (along the distance axis) and the amount of time needed (along the time axis). Examples of this type of work would be the installation of equipment (power substation) or the construction of retaining walls. Exhibit 2 shows such an activity in the area from km 1+100 until km 1+300, starting on Day 2 with a duration of 14 days. Activities which occupy a constant length of the line during a specific work period (assuming constant progress) would show as staggered line. Exhibit 3 demonstrates such an activity which starts in the area from km 1+900 to km 2+000 and requires one day to complete before the work crew moves towards the next line section (km 1+800 to km 1+900) to work there for one day. More complex activities will be drawn (such as overhead catenary installation) as parallelograms showing exactly during which time the line section is occupied by the work crew. Such an activity is shown in Exhibit 4 where the work