Rail Inspection RFP Manual for Ultrasonic Testing

A rail inspection RFP for ultrasonic testing is the technical specification a track owner issues to buy internal rail flaw testing. On FRA-regulated track it must cite 49 CFR 213.237 (intervals and valid search), 213.238 (qualified operators), 213.241 (records) and 213.113 (verification within four hours and remedial action), and then set equipment, reporting and acceptance terms.

This page is the specification half of the job. It gives the clauses a procurement engineer can copy into a scope of work, an evaluation table and a worked estimate of test shifts for a light-rail system. Who has jurisdiction over your track, which procurement method to use and how transit agencies run the solicitation are covered in our guide to rail inspection services for government transit authorities, so they are not repeated here.

Contents: What to specify · Regulations · Standards · USFD and track time · Sample clauses · Evaluation · Worked example · Mistakes · Limits · FAQ

What should a rail inspection RFP for ultrasonic testing specify?

A rail inspection RFP for ultrasonic testing should specify what rail is tested, to which rules, by whom, with what proof that the search was valid, how suspects are verified and marked, and what the deliverables are. Everything else, including price, depends on those six answers.

The original version of this article treated the RFP as a list of international standards. That misses how an internal rail test is actually judged. In the United States the test of a good contract is whether, at the end, the owner holds a record showing every foot of the specified rail either received a valid search or is listed as untested, and every indication was verified, sized and handed over for remedial action on time. The clauses below are written backward from that record.

A specification also has to say what it is not buying. Visual track inspection under 49 CFR 213.233, track geometry measurement, rail grinding and joint bar inspection under 213.121 are separate scopes with separate rules. If the RFP wants any of them, it should list them as separate line items rather than assume a rail flaw contractor will cover them.

Key takeaway: write the scope around the records the owner must keep, not around the equipment the bidder owns.

Which regulations does a rail inspection RFP have to cite?

On track that is part of the general railroad system, a rail inspection RFP has to cite five sections of 49 CFR Part 213 and the roadway worker rule that applies to the crew. The table lists them with the RFP clause each one drives.

The section that defines what the owner is paying for is 213.237(j)(4). The RFP should quote it word for word:

"Valid search means a continuous inspection for internal rail defects where the equipment performs as intended and equipment responses are interpreted by a qualified operator as defined in § 213.238." — 49 CFR 213.237(j)(4)

Two other paragraphs belong in the specification because they create contract obligations. Section 213.237(g) says that if the qualified operator determines a valid search could not be made over a length of track, that length "may not be considered as internally inspected". Section 213.241(c)(6) makes the location of that untested track a required record item. Together they mean the contractor must report gaps, not hide them.

Part 213 names no test method. The word "ultrasonic" does not appear in it; 213.237 requires "internal rail inspections" with equipment able to detect defects between joint bars (213.237(f)). Ultrasonic testing is the industry method, so the RFP should say the owner requires it rather than imply the regulation does.

Isolated rail transit that is not connected to the general system sits outside Parts 213 and 214 and under FTA Parts 671, 673 and 674 and the state safety oversight agency. Many such agencies adopt the 213.237 interval and the 213.113 table by their own standard. That jurisdiction question is the subject of our government transit authority guide; this page assumes you already know the answer and need the clauses. Track class itself is covered in our note on rail inspection RFP track classifications.

Key takeaway: quote 213.237(j)(4) in the scope, and the rest of the contract follows from it.

Which standards belong in a rail UT specification?

A rail UT specification should cite standards for what each one actually covers. EN 16729-1 and ISO 5735-1 are the in-track rail ultrasonic standards; ASTM E317 evaluates instrument performance; ASTM E164 and ISO 17640 are weld UT standards; EN 13674-1 is a rail product specification, not an inspection standard.

The original article called EN 13674 a "European rail inspection standard" and listed ASTM E317 and E164 as "US rail and structural testing" standards. Both descriptions are wrong, and a transit engineer who forwarded the page would be caught out. The corrected list:

Neither EN 16729-1 nor ISO 5735-1 covers grooved rail, so embedded street-running track on a light-rail system needs the agency's or the bidder's own procedure and a reference rail of the same section. The UIC 712 rail defect catalogue is useful for naming defects in a European context, but a US specification should use the defect names in 213.113(d), because those are the names that drive the remedial action table.

Key takeaway: if a standard in your draft RFP isn't in the left column of this table, check what it actually covers before you cite it.

What is USFD, and what does it need from the track owner?

USFD stands for ultrasonic flaw detection, the term used for rail testing on many railways outside North America. The original article expanded it as "Ultrasonic Speed Flaw Detection" and said it tests at line speed without interrupting traffic. Neither is right.

Any in-track ultrasonic test, by hi-rail vehicle, rail-bound car, walking cart or hand probe, needs track time. The crew is on or fouling the track, so it needs on-track protection, and on most transit systems that means working inside a non-revenue window. Vendors rate hi-rail test units at 30 to 45 mph, but a 1999 assessment for the Mountain-Plains Consortium (MPC 99-106) reported that test vehicles "typically average 6 to 8 mph" because they stop to hand-verify indications. Rated speed is not test speed.

The RFP therefore has to give bidders the access facts that set the price: the nightly window, how long it takes to obtain and release track, power-down arrangements on electrified track, and whether the owner or the contractor provides the roadway worker in charge. A bidder who has to guess these will either price the risk or underestimate the shifts. The comparison between stopping on every indication and recording first and verifying later is explained in our article on continuous vs stop-and-verify rail testing.

Key takeaway: state the track access window in the RFP; it drives the schedule more than the test speed does.

Sample RFP clauses: a template specification

The clauses below are a template, written as numbered specification text. Square brackets mark values the owner must choose. They are not legal advice and not a substitute for your agency's contract terms, and every bracketed number should be set by the owner's engineer. A Level III should review the equipment and calibration clauses against your rail sections before issue.

1. Scope

1.1 The Contractor shall perform an internal rail flaw inspection, by ultrasonic methods, of all running rail within the limits listed in Attachment A, including [main track, sidings, yard tracks, special trackwork as listed].

1.2 Attachment A gives, for each segment: track designation, beginning and end stationing or milepost, rail section and weight, rail type (tee rail or grooved), track type (ballasted, direct fixation, embedded), and the date of the last internal rail inspection.

1.3 Turnouts, frogs and rail crossings are [included / excluded]. Where included, the Contractor shall state in its proposal which components its method can examine and which it cannot.

1.4 This scope excludes visual track inspection under 49 CFR 213.233, track geometry measurement and joint bar inspection unless listed as separate pay items.

2. Governing requirements and standards

2.1 On track subject to 49 CFR Part 213, the work shall satisfy 49 CFR 213.237, 213.238, 213.241 and, where continuous testing is used, 213.240. Defect names and verification shall follow 49 CFR 213.113.

2.2 On track not subject to Part 213, the Owner adopts the requirements in 2.1 as contract requirements, together with the Owner's [track standard / SSOA-approved procedure, title and revision].

2.3 The Contractor's written procedure may reference EN 16729-1 or ISO 5735-1 for test principles. Where a reference standard does not cover a rail section in Attachment A (for example grooved rail), the procedure shall describe the technique and reference rail used for that section.

2.4 Where documents conflict, the order of precedence is: federal regulation, this specification, the Owner's track standard, the Contractor's approved procedure.

3. Equipment and calibration

3.1 The Contractor shall describe each test system proposed: platform (rail-bound vehicle, hi-rail vehicle, walking cart, hand instrument), number of rails tested per pass, probe angles and their aim, coupling method and data recording.

3.2 The system shall be capable of detecting defects within the rail between joint bars (49 CFR 213.237(f)). A typical arrangement uses 0° probes and angled probes, commonly around 37–45° and 70°, with side-looking channels; the Contractor shall state its actual configuration and the defect types each channel is intended to detect.

3.3 The Contractor shall verify system sensitivity on a reference rail containing artificial reflectors, of a section representative of the rail under test, at the start of each shift and [at the end of each shift / at intervals stated in its procedure]. Results shall be recorded.

3.4 Instruments used for hand verification shall be checked for performance characteristics at intervals stated in the Contractor's procedure, using ASTM E317 or an equivalent method, and calibrated on a recognized block before use. The procedure shall state the reference reflector and how the evaluation level is set (for example a DAC).

3.5 Phased array instruments may be offered for verification. They are not required.

The calibration clauses are hedged on purpose. North America has no standardized calibration procedure for handheld rail UT, a gap noted in FRA research report DOT/FRA/ORD-26/07 (2026), and no public primary source sets a standard vehicle method. Asking for the bidder's procedure and the recorded results is more defensible than inventing a number. Our separate post on ultrasonic testing calibration in a rail inspection RFP goes further, and how a DAC curve is built explains the hand-verification reference.

4. Personnel qualification

4.1 Each person who operates rail flaw detection equipment or interprets its responses shall be a qualified operator under 49 CFR 213.238 for the specific equipment type used.

4.2 With its proposal the Contractor shall submit: its documented training program summary; for each proposed operator, name, equipment types qualified on, date of qualification and date of last reevaluation (213.238(e)); and its written practice for UT personnel under SNT-TC-1A or CP-189.

4.3 Hand verification of suspects shall be performed by a person qualified under 213.238 and certified by the employer to at least UT Level II under the Contractor's written practice. A Level III shall approve the Contractor's procedure.

4.4 Roadway worker training for each crew member shall be current under [49 CFR 214.343 / the Owner's Part 671 program].

5. Valid search

5.1 The Contractor shall perform a valid search as defined in 49 CFR 213.237(j)(4) over the full length of each rail in Attachment A.

5.2 The operator shall determine continuously that the equipment is performing as intended and that the search has not been compromised by contamination, rail condition or equipment malfunction (213.238(b)(2) and (b)(4)).

5.3 Any length where a valid search was not obtained, for example loss of coupling, surface condition or equipment fault, shall be recorded as untested with its start and end location and reason, and reported to the Owner [before the end of the shift].

5.4 The Contractor shall retest untested lengths [within the same mobilization / at the Owner's direction]. Retests caused by the Contractor's equipment or procedure are at the Contractor's cost.

6. Suspect verification and marking

6.1 Each indication of a possible internal defect (a "suspect") shall be verified in the field by hand ultrasonic examination before the crew leaves the location, unless the Owner has approved continuous testing under 6.4.

6.2 For each verified defect the Contractor shall record location, defect type using 49 CFR 213.113(d) names, and size (percent of head area, or length, as the defect type requires).

6.3 Each defective rail shall be marked with a highly visible marking on both sides of the web and base, or on or next to the head where a side is inaccessible because of permanent features (213.237(e)). Marking colour and format: [Owner standard].

6.4 Where continuous testing under 49 CFR 213.240 is approved, suspects shall be listed, prioritized and field-verified within the time limits of 213.240, and no suspect shall be treated as cleared until field-verified by a 213.238 person.

7. Notification and reporting timelines

7.1 The Contractor shall notify the Owner's designated person by [telephone] immediately on verifying any defect that may require remedial action A, A2 or B under the 213.113 table, and before leaving the location for any other verified defect.

7.2 Notification shall include location, rail, defect type and size, and any broken rail or separation found.

7.3 A daily summary listing tested limits, untested lengths, suspects, verified defects and notifications shall be delivered within [12] hours of the end of each shift.

7.4 The final report shall be delivered within [10] working days of completing the field work.

The reason for 7.1 is the clock in 213.113(b). The owner, not the contractor, "must verify the indication within four hours", or immediately for defects requiring remedial action A, A2 or B, and that clock starts when the owner learns of the indication. A contract that lets the contractor hold findings until morning puts the owner in breach.

8. Deliverables and records

8.1 The Contractor shall deliver records containing, for each inspection, the items in 49 CFR 213.241(c): date; track inspected with beginning and end points; location and type of defects; size of defects not removed before the next train; initial remedial action taken and date (completed by the Owner where the Owner takes it); and location of any track not tested.

8.2 Deliverables shall also include: calibration and sensitivity records for each shift; operator names for each run; the daily summaries; and data in [format, e.g. CSV with stationing and GPS coordinates].

8.3 Where records are electronic, the system shall uniquely identify each author, prevent modification of completed records, and store amendments separately (213.241(j)). Storage of each record shall be initiated by the person making the inspection within 72 hours of completing it.

8.4 The Owner retains records for at least two years after the inspection and one year after initial remedial action (213.241(d)). The Contractor shall retain its copies for [3] years.

9. Safety

9.1 On track subject to 49 CFR Part 214, all work shall be performed under Part 214 on-track safety, including a job briefing before fouling (214.315) and working limits established by the [Owner / Contractor] roadway worker in charge.

9.2 On a rail transit system subject to 49 CFR Part 671, the Contractor shall work under the Owner's SSOA-approved roadway worker protection program. Briefings on electrified track shall include the status of power and electrified-system hazards (671.33(b)(3)).

9.3 The Contractor shall submit a site-specific safety plan covering access, electrical hazards, couplant handling and night work [at least 10 working days before mobilization].

10. Acceptance of the work

10.1 The work is accepted for a segment when the Owner receives records showing that 100% of the rail in Attachment A for that segment was either validly searched or listed as untested with reasons, and every suspect was verified and reported.

10.2 Acceptance does not depend on the number of defects found.

10.3 The Owner may audit the work by [witnessing calibration, re-examining a sample of verified locations, or running a blind test on a reference rail].

10.4 Untested lengths retested under 5.4 are accepted on receipt of their records.

Key takeaway: clause 10.1 is the one that protects the owner; it turns the 213.241 record into the acceptance test.

How should rail UT proposals be evaluated?

Rail UT proposals should be evaluated against the same clauses the contract will enforce, so each criterion asks the bidder for evidence it will later have to deliver. Price matters, but the weighting is the agency's decision under its own procurement rules.

The original article said "most successful procurement programs" use a 70/30 technical-to-price split. No source supports that figure, and it has been removed. Transit procurement rules, including the choice between low bid and best value, are covered in the government transit authority guide.

Asking for a sample record and a sample calibration sheet is the fastest way to separate bidders. A contractor who can't show one before award is unlikely to produce one after. The ultrasonic rail inspection checklist can be attached as an evaluator's reference.

Worked example: how many test shifts does a 40-mile light-rail RFP need?

A 40-route-mile double-track light-rail system needs roughly 15 night shifts of testing and verification under the planning assumptions below. Suspect rate, not test speed, is the input that moves the answer most.

Every rate in this example is a planning assumption chosen to show the method. None is an industry statistic. Replace them with the agency's past test data and the bidders' stated rates.

Inputs

Tee rail by test vehicle

Moving at 10 mph takes 6 minutes per track mile. One suspect per mile at 10 minutes adds 10 minutes. Each track mile therefore takes 16 minutes, an average of 3.75 mph.

72 track miles × 16 min = 1,152 min = 19.2 h. At 3.0 productive hours per shift, that is 6.4 shifts, rounded up to 7 shifts. Verification is 720 of the 1,152 minutes, or 62.5% of the time.

Grooved rail by walking cart

At 1.5 mph the cart takes 40 minutes per rail mile. Two suspects at 10 minutes add 20 minutes, so each rail mile takes 60 minutes.

16 rail miles × 60 min = 16 h, or 5.3 shifts, rounded up to 6 shifts.

Retests and lost shifts

If 5% of the length needs a retest after an invalid search, the vehicle adds 3.6 track miles × 16 min = 57.6 min, and the cart adds 0.8 rail miles × 60 min = 48 min. That is about 1.8 h, so allow 1 shift. Allow 1 more shift for a possession lost to weather, an incident or a late release.

With one crew working four nights a week, 15 shifts is about four weeks of nights. Two crews on different segments could halve the calendar time, but only if the agency can grant two possessions a night.

How sensitive is the answer to the suspect rate?

Doubling the suspect rate from 1.0 to 2.0 adds four vehicle shifts. Doubling the moving speed from 10 to 20 mph, at 1.0 suspect per mile, cuts each mile from 16 to 13 minutes and saves only about one shift (15.6 h, or 6 shifts). That is why the evaluation table asks for the bidder's verification method rather than its top speed.

Verification output

Total suspects are 72 on tee rail plus 32 on grooved rail, 104 in all. If, as a further assumption, one in ten verifies as a defect, the crew will mark and report about 10 defects. Each needs notification under clause 7.1, a 213.113(d) name and size, and a marking under clause 6.3. The rest are recorded as verified benign. Our page on false calls in rail UT explains why benign suspects are normal and why lost coupling is untested rail, not a false call.

The figures in this example are planning numbers only. A real light-rail program will differ on access time, curves, stations, crossovers and special trackwork, and the metro and light rail testing guide covers the field conditions that drive those differences.

What mistakes weaken a rail inspection RFP?

The mistakes that weaken a rail inspection RFP are the ones that leave the owner without a defensible record: no valid search definition, no untested-track reporting, no notification clock and standards cited for the wrong purpose.

• No valid search clause. Without 213.237(j)(4) in the contract, a report of "miles tested" can include rail the system never coupled to.
• No untested-length requirement. If the contract doesn't require 213.241(c)(6) data, gaps disappear from the report.
• Notification left to the final report. The 213.113(b) four-hour clock starts when the owner learns of the indication.
• Weld or product standards cited for rail flaw detection. ISO 17640, ASTM E164 and EN 13674 do not specify in-track rail testing.
• A required technology instead of a required result. Mandating phased array, or a fixed probe count, excludes bidders without improving the search. Ask what each channel detects instead.
• Rated speed used to plan the schedule. Plan from the access window, verification time and suspect history.
• Grooved rail not identified. The in-track standards don't cover it, so the bidder needs to know before pricing.
• Pre-2014 intervals copied from an old RFP. The current Class 4–5 rule is 370 days or 30 MGT, not "annual or 40 MGT". See how often rail must be tested.

What a rail UT specification can't do

A rail UT specification can set a valid search and a verification process, but it cannot make ultrasonic testing find every defect. Detection depends on defect size, orientation and the rail surface, and the contract should say so rather than promise otherwise.

Shells, head checks and heavy surface damage can mask what lies beneath them, especially detail fractures, which can grow from shelled spots and head checks. Vehicle testing covers the head, the web and the part of the base directly under the web; the base flanges are largely outside the beam. Bolt holes, welds and special trackwork are harder, and cast manganese frogs are coarse-grained enough that in-service examination is usually visual. FRA research on hand-held rail UT (DOT/FRA/ORD-26/07) found that operators rarely produced statistically similar calibration results, which is why clause 3.3 asks for recorded checks rather than trust.

Part 213 requires no detection rate, and no clause should promise 100% detection. What the contract can require is coverage that is proven by records, untested track that is reported, and suspects that are verified on time. Rail grinding, wear measurement and joint bar condition need their own scopes.

How EMA Industries applies this

EMA Industries provides ultrasonic rail flaw testing for transit agencies, short lines and industrial track owners from its base in Southern California, and mobilizes nationwide. When an RFP includes the clauses above, EMA prices to the owner's access window, verifies suspects by hand on site, reports untested lengths and delivers records built around the 213.241 items, with NDT Level III review of the procedure. To discuss a scope of work or a draft specification, contact EMA Industries.

Related reading: Ultrasonic rail testing services in the USA · Ultrasonic rail inspection checklist · Ultrasonic rail testing for metro and light rail systems · 49 CFR 213.237 explained · Rail inspection RFP guide

Frequently asked questions

What should a rail inspection RFP require for ultrasonic testing?

It should require a valid search under 49 CFR 213.237(j)(4), operators qualified under 213.238, hand verification of every suspect, immediate notification for defects that may need remedial action A, A2 or B, marking under 213.237(e), and records containing the six 213.241(c) items, including untested track.

Does an RFP have to require phased array ultrasonic testing?

It doesn't, and it shouldn't by default. No federal rule requires phased array for rail, and test vehicles use conventional multi-channel probes. Phased array can help with hand verification, so an RFP may allow it, but requiring it limits bidders without improving the valid search.

Which standard covers ultrasonic testing of rails in track?

In Europe, EN 16729-1; internationally, ISO 5735-1:2024. Both cover flat-bottom rail only and not grooved rail. In the United States the governing requirements are FRA's 213.237 and 213.238, which set results and qualifications rather than a test technique.

How long does it take to test a light-rail system?

It depends on the nightly access window and the suspect rate more than on test speed. In our worked example, 40 route miles of double track needed about 15 night shifts with a 3-hour productive window. Use your own access times and test history to replace the assumptions.

Who verifies a suspect found during rail testing?

A person qualified under 49 CFR 213.238 hand-verifies it, normally a UT Level II on the test crew. The track owner then has the 213.113(b) duty to verify the indication within four hours, or immediately for A, A2 or B defects, so the contract should give the owner the finding at once.

Sources

• 49 CFR 213.237, Inspection of rail, eCFR (text read on Cornell LII, October 2026)
• 49 CFR 213.238, Qualified operator, eCFR
• 49 CFR 213.240, Continuous rail testing, eCFR
• 49 CFR 213.241, Inspection records, eCFR
• 49 CFR 213.113, Defective rails, eCFR
• 49 CFR Part 214, Railroad workplace safety, eCFR
• 49 CFR Part 671, Rail transit roadway worker protection, eCFR
• EN 16729-1:2016 scope, Genorma listing
• ASTM E317-21 and ASTM E164-24, ASTM store listings
• ANSI/ASNT CP-189 and SNT-TC-1A, ASNT standards page
• Assessment of Rail Flaw Inspection Data, MPC 99-106, Mountain-Plains Consortium, 1999
• DOT/FRA/ORD-26/07, model-assisted probability of detection for handheld rail ultrasonic testing, Bruzek, Einbinder and Tunna (ENSCO) for FRA, July 2026