Section 3: Federal Railroad Grade Separation Program
Anchor: #i1009493Overview
This program addresses:
- construction of new grade separation structures at existing at-grade highway-rail crossings
- rehabilitation or replacement of deficient highway underpasses of railroads on the state highway system
The eligible state highway system routes must be of a classification greater than local road or rural minor collector on the functional classification scale, i.e., they must be classified as federal-aid highways.
Selected and prioritized highway-rail grade separation projects are in some instances authorized in funding Category 6 RGS of the yearly Unified Transportation Program (UTP) under the CONSTRUCT level of authorization. Approximately 50% of the available Category 6 RGS funding is targeted for each of the following:
- new grade separation structures
- remedy of deficient railroad underpasses
Candidate projects for construction of new grade separation structures are prioritized using a cost-benefit index (CBI), and projects for railroad underpass replacement/rehabilitation are prioritized using a priority rating (PR).
Anchor: #i1009861Work Limitations
Funding from Category 6 RGS in these projects should be limited to the actual structure and other work necessary to make the structure serviceable consistent with good design. This limits Category 6 RGS-funded approach roadway work to that sufficient to transition the gradeline of the structure to an attainable touchdown with the existing or new approaching roadway that is at or near level grade. Roadway and other work that is outside these limitations should be funded from other categories.
These limitations should particularly control when the new or replacement structure will be constructed on new alignment or new location.
Normally the existing at-grade highway-rail crossing occasioning construction of the new grade separation structure should be eliminated.
Anchor: #i1009994Prioritization of New Highway-Rail Grade Separation Projects
The cost-benefit index (CBI) used in prioritizing new highway-rail grade separation projects is the estimated cost in millions of dollars that would be saved in highway user cost over a 50-year design life of the new grade separation structure constructed at the existing highway-rail crossing. The higher the estimated user cost, the higher the priority. The estimated user cost includes cost due to casualties (fatalities and injuries) and personnel and traffic equipment delay.
Factors used in calculating a CBI are as follows:
- Average daily traffic
- Number of train movements
- Number of highway fatalities, injuries, and property damage only (PDO) crashes
- Period (range) in years for which casualty data are available
- Estimated yearly costs for personnel and equipment delays (due to waiting for trains to pass)
The data described for CBI calculation are provided from the Roadway Information System (RIS) compiled by the Transportation Planning and Programming Division (TPP).
Further information on the CBI formula is provided in Basis of Calculations for the CBI. (See the Bridge Division’s internal Project Development web pages at http://crossroads/org/brg/.)
NOTE: Access to the internal web site is available only to TxDOT personnel.
Anchor: #i1010365Prioritization of Railroad Underpass Replacement/Rehabilitation Projects
Projects for railroad underpass replacement/rehabilitation are prioritized using a priority rating or score on a numerical scale of 0 through 100. The higher the rating number, the less sufficient the structure for underpassing highway traffic, and thus the higher the priority for replacement/rehabilitation.
The attributes and relative weights used in calculating a priority rating score are as follows:
- Underpassing roadway width - 20%
- Vertical underclearance - 20%
- Right lateral underclearance - 20%
- Average daily traffic (underpassing) per lane - 20%
- Estimated construction cost per Average Daily Traffic (ADT) - 20%
This rating calculation uses the bridge inspection database appraisal ratings (0 through 9) for the underpassing roadway width, vertical underclearance, and right lateral underclearance features. The bridge inspection database provides ADT and number of underpassing lanes items.