Not every feature in the base_roads feature class has route and measure information. Before you create any routes from the data, you will want to select the roads that contain this information. It would be pointless to create routes without this information.

Creating a temporary layer allows you to do things, such as make selections, without affecting the original data source. This layer will not appear in the ArcCatalog contents, because it is created in-memory and simply references the data stored on disk. These layers can be used as inputs to other geoprocessing tools within your working session. Once you exit the application the in-memory layers will be removed.

You can open the ArcToolbox window in ArcCatalog by clicking the Show/Hide ArcToolbox button on the Standard toolbar.

You can click the top of the ArcToobox window and drag it around the ArcCatalog window to dock it where you prefer. Also, you can double-click the top of the window to undock or dock it.

The Make Feature Layer tool is in the Layers and Table Views toolset, within the Data Management Tools toolbox. Right-click the Make Feature Layer tool and click Open, or double-click it to open the tool.

There are several ways to set the input feature class for a geoprocessing tool. You can drag a feature class from the ArcCatalog tree and drop it onto the text box, click the Browse button and navigate to the feature class in the dialog box, or simply type the full pathname to the feature class in the text box.

This layer will have a query, to select the roads with route information. To build an expression for a layer, click the Expression button to open the Query Builder. Type an expression like “"ROUTE1" <> 0” in the text box, then Click OK to close the Query Builder.