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I'm trying to use train tracks as a network in ArcGIS Network Analyst.

We are trying to create a model for security agents on board our trains and we'd like to optimize their daily "route". For now, it's all made by hand.

My approach is to take our gtfs data and create a network using stop times to determine when the train segment is "traversable". When there's a train on the segment, it's open, if not, it's restricted.

The problem is I can't set a restriction based on time in Network Analyst (or wasn't able to). I would like to be able to say by a formula or script than you can take that segment only from 7:03 AM to 7:10 AM for example.

Is it possible?

Thanks!

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What you want to do is possible, but not in the manner you're thinking.

A network could generally be considered static in that the rules and restrictions for the edges are governed by single, static values. Accounting for change and time of day is another level known as Traffic.

You may want to read through this ArcGIS help page for a detailed explanation, but basically either storing a variety of values for a single edge or multiple networks with varying values would take up too much space. Instead, the travel time properties (or a profile) for an edge are referenced from a lookup table based on time of day.

What you need to do is create historical traffic data for your network based on the train schedule. There are several tutorials and help pages that can assist you with this, but covering the whole process would be too long for a SE question/answer.

  • Many thanks! On a related matter, how would you add time restriction for a turn table? Like to restrict left turn only from 22pm to 7am at an intersection? – fgcartographix Jun 12 '14 at 12:18
  • @fgcartographix I'm not 100% sure; I believe the traffic profile does/can apply to turns. Turns can have an impedence or delay just as edges do, so in setting up the traffic data for that window you would just change that turns impedence to a high value/infinite. I haven't actually tried to do time based turn restrictions before. – Chris W Jun 12 '14 at 18:29
  • I (think I) remember doing it at school... in '93... – fgcartographix Jun 13 '14 at 19:22

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