topic Re: Creating a Rail network dataset? in ArcGIS Network Analyst Questions

Creating a Rail network dataset?

BenKeller2 — Mon, 12 Nov 2012 16:35:54 GMT

Has anyone created a Network Dataset for rail? I am trying to create one from http://cta.ornl.gov/transnet/RailRoads.html which has a lot of good data but unfortunately I am new to Network Analyst. The Paris example makes it seem straight forward, but unfortunately it is not with this rail dataset. Any words of wisdom would be greatly appreciated. I just dont want to have problems with turns and hierarchy which is very restrictive for rail cars.

Thanks
Ben

Re: Creating a Rail network dataset?

RamB — Mon, 12 Nov 2012 19:08:47 GMT

Hallo,

Please explain what is your objective after creating the network ?

regards,

Re: Creating a Rail network dataset?

BenKeller2 — Tue, 13 Nov 2012 12:47:26 GMT

I work for an asset management firm and we want to be able to analyze routes based on our historical data of how long our assets sit in facilities and how long they typically take during their travel between them. We want to be able to give accurate information of ETA's to our customers. Obviously we understand that it will not be 100% accurate but some estimations are better than nothing. This dataset has a lot of useful information, but the description of the attributes is out of date and it does not build very well. I am trying to incorporate some restrictions for turns mostly some simple ones such as acute angles, and hierarchy since there is an attribute for main lines and etc., but I cannot seem to figure it out. Obviously a train should not be able to make this turn, and the node incorporated with that intersection does not label it as a switch and has nothing in the turn attribute column. The turn attributes consist of A,E,U,M,S,T,X,Y, Z, and blank. Without a correct description I am not sure what I can actually do with this dataset. Maybe you know a more reliable dataset? Any help would be great!

Thanks
Ben

Re: Creating a Rail network dataset?

RamB — Wed, 14 Nov 2012 05:56:23 GMT

Hi,

Thanks. I do deal with asset management but is not bread and butter 🙂

option1: Suggestions based on the example picture that you attached, do not make the intersection break at that point. So in edit mode, you select the two line segments that form a feasible rail route and select the merge option from the edit menu. Ofcourse, this will work if you have not a lot of such intersections.

option2: Other than the image, i suggest that you first make a route layer, that is the entire path a train would take from its origin to destination and this should be done for each possible route. Then, split your each route at vertices. After you do this, use the Linear Directional Mean tool with ID as a case. This will give you angle(bearing) of each line segment. For rail, the difference in bearing of successive line segments should not be huge, as you already pointed out.

The above helps you to identify points of wrong turns and you can manually correct them as in option 1

option3: after doing the above, if you find out that there are exception routes that do have a sharp turn while other trains at the same intersection do not and if it is not possible to generalize. Then add and extra line segment with different elevation field for that line. see picture.

yes, it is manual work !

My english is not the best, so please ask again if not clear.

Re: Creating a Rail network dataset?

BenKeller2 — Wed, 14 Nov 2012 11:41:57 GMT

Thanks a lot for your help! I will look into that, and see what I can do. The problem may be that I have an entire rail network of North America that I am working with. A full manual work around for it could be a bit time consuming.

Re: Creating a Rail network dataset?

RamB — Wed, 14 Nov 2012 15:33:12 GMT

Yes, I suggest that atleast that the routes be made. It will help your cause a lot. And routes with combination of elevation fields will take your project a long way and bring clarity to your model. Not sure if you already have it as such (one line feature for one rail route).

regards,

Re: Creating a Rail network dataset?

BenKeller2 — Tue, 20 Nov 2012 12:04:47 GMT

Another question, if I wanted to make sure that routes are only taken on the same rail by ownership (not specifically one owner) but a function that would limit a route to stay on that same owner rail based on where I start the route. How would I write that function?

Re: Creating a Rail network dataset?

RamB — Tue, 20 Nov 2012 14:55:40 GMT

Hi,

you can make use of elevations. each owner can have own elevation. shortest path does not criss-cross across different elevations. It can be imagined as something like the mobile phone spectrum allocation.

See step 20 here "There are two ways to model elevations: using true elevation values from geometry or using logical elevation values from elevation fields. "

regards,

Re: Creating a Rail network dataset?

BenKeller2 — Tue, 20 Nov 2012 17:04:22 GMT

I don't have an elevation field and my Owner field is a text field not an integer.

Re: Creating a Rail network dataset?

NicoleHanson — Tue, 20 Nov 2012 17:07:08 GMT

Are you able to add fields, or is the data a read only?

Re: Creating a Rail network dataset?

BenKeller2 — Tue, 20 Nov 2012 17:17:17 GMT

Yea I guess I could add a field. It's from http://cta.ornl.gov/transnet/RailRoads.html . Plus it probably does not help that this is my first time creating a network dataset and using network analyst. Have you worked with this dataset before or any rail network? Network analyst seems to be more road friendly than rail.

Re: Creating a Rail network dataset?

NicoleHanson — Tue, 20 Nov 2012 17:35:44 GMT

Yea I guess I could add a field. It's from http://cta.ornl.gov/transnet/RailRoads.html . Plus it probably does not help that this is my first time creating a network dataset and using network analyst. Have you worked with this dataset before or any rail network? Network analyst seems to be more road friendly than rail.

I have not worked with rails, but I have created a network dataset from scratch, and have worked with network analysis exclusively for the past 5 months.

In my understanding, rails are very similar to roads. Let me see what I can do from my end to help you.

Re: Creating a Rail network dataset?

NicoleHanson — Tue, 20 Nov 2012 17:40:21 GMT

To start, this is a great resource I used when creating and modifying my network: http://support.esri.com/en/knowledgebase/techarticles/detail/32890

There is the option when creating the ND to use global turns, that will be helpful. Also, with Hierarchy, it's actually very easy to use. You would need to add a field if there isn't already one.

Re: Creating a Rail network dataset?

BenKeller2 — Tue, 20 Nov 2012 18:12:42 GMT

There is a hierarchy type field, just saying Main Lines and what not. The dataset actually has a lot of useful data, just my understanding of parameters and evaluators is slowing me down. Thanks a lot though! That would be great.

Ben

Re: Creating a Rail network dataset?

NicoleHanson — Tue, 20 Nov 2012 18:21:44 GMT

Gotcha, then I would check out the last part of that document. It talks about the Parameters and Evaluators. What worked best for Hierarchy though, is using a numeric set up vs the text.