MARTA trains travel southbound from the north and northeast lines and merge at Lindbergh Center Station. With trains, it is extremely important to avoid collisions. Therefore, segments of track are considered as resources with only one train allowed in a segment at a time. A train \"seizes\" its next section of track and can enter only if it is empty. Otherwise, it stops. Use process-interaction blocks to model the movement of north line trains from Buckhead Station to Lindbergh Station to Arts Center Station and the movement of northeast line trains from Lenox Station to Lindbergh Station to Arts Center Station. Here are some points to consider. 0 Arrivals of both train types to their rst stations are Triangular (3.8, 4, 4.2) 0 Each station and the section of track between it and the preceding station are considered a segment. For Lindbergh Center Station, this includes both tracks to the preceding stations. A train cannot leave a station without seizing the segment ahead of it. o The travel time from exit of one station to exit from another is Triangular (3,5, 4, 4,5). 0 The train entities need to be identied as either 1 (north line) or 2 (northeast line) when they are created. 0 Most importantly, there is a switch before the Lindbergh Center Station. It must be set to 1 to allow a north line train to join the track or 2 to allow a northeast line train to join the track. Otherwise, there will be a derailment. (Hint: The switch should be set after the train leaves the queue for the Lindbergh Center Station but before it starts travel.)