Slow Order Railroad: What Happens When a Rail Defect Is Found

Slow order railroad rules for a defective rail come from 49 CFR 213.113. The track owner must verify a defect indication within 4 hours, or immediately if it calls for remedial action A, A2 or B. It then replaces the rail or applies the lettered remedial action, which can mean a supervised move, a 10, 30 or 50 mph limit, joint bars or reinspection.

A "slow order" is the railroad's name for the temporary speed restriction that carries out that remedial action in the field. The federal rule sets the minimum response; the railroad's own operating rules and bulletins decide how train crews are told. This page follows the process from the first indication to the day normal speed returns. For the defect definitions themselves, see our guide to FRA defect codes.

Contents: What a slow order is · What 213.113 requires · Verification time · Remedial notes A–I · The remedial action table · Worked example · Issuing and lifting a slow order · 213.9 and 213.5 · Continuous testing · Limits · FAQ

What is a slow order on a railroad?

A slow order is a temporary speed restriction placed on a defined stretch of track, between two mileposts, because of a condition that has changed. It differs from the permanent maximum speed in the timetable, which reflects the track class and the route's normal characteristics.

Railroads issue slow orders for many reasons: heat, disturbed track after surfacing, geometry defects, washouts and rail defects. This article covers the rail defect case, because that is the one where a federal table prescribes the speed. Under 49 CFR 213.113, many defect types and sizes carry a specific speed limit until the rail is replaced or repaired.

"Slow order" is an informal term. Operating rulebooks usually say "temporary speed restriction" and deliver it in a written bulletin or order. How that works is covered further down, in the section on issuing and lifting a slow order.

Key takeaway: the slow order is how the railroad tells crews about a remedial action; 213.113 decides what that action must be.

What does 49 CFR 213.113 require when a rail defect is found?

Section 213.113 sets three steps: decide whether the track can stay in use, verify the indication, and then replace the rail or apply the remedial action in its table. Paragraph (a) puts the first decision on a qualified person:

"a person designated under § 213.7 shall determine whether the track may continue in use. If the designated person determines that the track may continue in use, operation over the defective rail is not permitted until— (1) The rail is replaced or repaired; or (2) The remedial action prescribed in the table contained in paragraph (c) of this section is initiated." — 49 CFR 213.113(a)

That sentence answers the title question. No train may pass over a confirmed defect until either the rail is fixed or the remedial action has started. The remedial action is often a speed limit, and the slow order is how that speed limit reaches the crews.

The rest of the section is organized like this:

The "person designated under 213.7" is someone the track owner has designated as qualified for track maintenance or inspection. FRA doesn't certify these people; the owner designates them and keeps the records. Section 213.113 applies to Class 1 to 5 track. Class 6 and higher track uses the parallel table in 49 CFR 213.337, which differs in places (its note C allows 20 days for joint bars, not 10).

Key takeaway: confirmed defect, then a decision by a designated person, then repair or remedial action before the next move.

How fast must a rail defect indication be verified?

Under 213.113(b), the track owner must verify an indication within four hours, or immediately if the suspected defect would require remedial action A, A2 or B. The rule reads:

"Except as provided in § 213.240, the track owner must verify the indication within four hours, unless the track owner has an indication of the existence of a defect that requires remedial action A, A2, or B … in which case the track owner must immediately verify the indication." — 49 CFR 213.113(b)

Two details matter in the field. First, the clock starts when the owner "learns" of the indication. If a testing contractor finds the indication, the time it takes to tell the owner's roadmaster or dispatcher is part of the owner's four hours, so the hand-off has to be fast and written down. Second, "verify" means confirming the defect and its type and size, normally by hand testing at the marked spot. Once verified, the owner must replace or repair the rail, or initiate the remedial action in the table.

The 36- and 84-hour windows apply only to an owner using continuous rail testing under 213.240. They are not general response times for every defect, which is a common error in draft compliance material.

Key takeaway: four hours is the normal limit, "immediately" applies to the worst defects, and only continuous testing changes the clock.

What speed does each remedial action note impose?

Each letter in the remedial action table points to a note, and most notes set a speed or a deadline. The notes below are summarized from the 2014 rule text, which is still the current table, with each speed capped at the 213.9 maximum for the track class where the note says so.

Source: remedial action notes in Track Safety Standards; Improving Rail Integrity, 79 FR 4234 (January 24, 2014), page 4257. Class 2 speeds are 25 mph freight and 30 mph passenger under 49 CFR 213.9.

Note A is often described as "stop the train". That isn't what it says. Note A requires a designated person to watch every movement over the rail, and the rail can't carry traffic without that person. In practice that may stop trains until someone arrives, but the rule's requirement is supervision, not a set speed of zero.

Under F and G, the reinspection repeats until the rail comes out, unless the defect has grown into a size band with a more restrictive action. A growing defect moves up the table.

Key takeaway: A and A2 control each move, B and I mean 30 mph, H means 50 mph, and C and D add joint-bar deadlines of 10 and 7 days.

Which remedial action applies to which defect?

The remedial action depends on the defect type and its size, measured either as a percentage of the rail head cross-section or as a length in inches. The table below follows 213.113(c). Each defect group has its own size bands; don't mix them.

Defects sized by percentage of rail head area weakened:

Defects sized by length:

Source: 49 CFR 213.113(c); table text read from the 2014 Federal Register rule, because online CFR copies display the table as an image.

Notice the compound fissure row. A compound fissure of only 5% gets action B, while a transverse fissure of the same size gets C. That's why the two defects are covered separately: see compound fissure in rail for that defect's growth and detection, and transverse fissure in rail for this one.

The table has no row for shelling, head checks, corrugation or rail wear. A slow order for those conditions, if a railroad issues one, comes from its own engineering standards, not from 213.113.

Slow order railroad worked example: a 30% transverse fissure

This example follows one defect from the test car to the rail change, using the rule text above. The track and times are illustrative; the rule steps are real.

Inputs:

• Class 4 freight main line, timetable speed 60 mph (the Class 4 freight maximum in 213.9)
• Annual traffic: 40 MGT
• Internal rail test under 213.237 with a stop-and-verify test car (not continuous testing, so 213.240 doesn't apply)
• Indication in the head of the south rail at milepost 112.40, found Tuesday at 09:10
• Hand verification sizes it as a transverse fissure weakening about 30% of the head area

Step 1: which remedial action? 30% falls in the 25% to under 60% band, so the table gives action D. D is not A, A2 or B, so the verification deadline is four hours.

Step 2: the timeline.

Step 3: check the deadlines.

• Verification: 25 minutes against a 4-hour limit, so the owner is well inside 213.113(b).
• Joint bars: note D allows 7 days from the decision to keep the track in use. That decision was Tuesday 09:45, so the bars were due by the following Tuesday 09:45. They went on after 28 h 25 min (Tue 09:45 to Wed 14:10).
• Speeds: 30 mph until barred (at or below the D limit), then the lower of 50 mph and the 60 mph class maximum, which is 50 mph.
• If the bars had not gone on by the following Tuesday 09:45, the speed would have dropped to 10 mph until they did.

Step 4: what the slow order cost in running time. Assume a 7,000 ft (1.33 mile) freight train. Under most operating rulebooks the train holds the restricted speed until its rear end clears the far milepost, so it runs 0.20 + 1.33 = 1.53 miles at the restricted speed. At 30 mph that takes 1.53 ÷ 30 × 60 = 3.06 minutes. At 60 mph it would take 1.53 minutes. Each train loses about 1.5 minutes plus braking and acceleration time. At 50 mph the same stretch takes 1.84 minutes, a loss of about 0.3 minutes. Check your own rulebook for when a train may resume speed.

Step 5: check the plug rail. Under 213.237(c), the owner must verify that plug rail installed after March 25, 2014 has not accumulated more than 30 MGT, in its old and new locations combined, since its last internal test, before the next required test on that rail. Suppose the plug rail carried 18 MGT in its previous location after its last test. The margin is 30 − 18 = 12 MGT. At 40 MGT a year, 12 ÷ 40 = 0.30 years, or about 110 days. If the segment's next scheduled internal test is more than about 110 days away, the plug rail needs its own test first, or trains over it are limited to Class 2 speeds (25 mph freight) under 213.237(c)(3). Our relay rail inspection guide covers second-hand and plug rail in more depth.

Step 6: records. Because the defect stayed in track past the next train, the inspection record under 49 CFR 213.241 must show its location, type and size, and the initial remedial action and its date. The record is kept at least two years after the inspection and one year after the initial remedial action.

The same defect at other sizes. Run the same indication through the table at different sizes and the response changes sharply:

If the same 30% indication had been a compound fissure, the action would be B: verification immediately, and no more than 30 mph set by an experienced designated person. B has no joint-bar step, so the rail has to come out.

How is a slow order issued and lifted in practice?

In practice a slow order goes out as a written temporary speed restriction from the dispatcher or the railroad's bulletin system, with milepost limits and a speed, and stays in force until the railroad formally cancels it. Part 213 says what speed is required; it doesn't say how the crew is told. That is set by the railroad's operating rulebook.

The details vary by railroad and rulebook, so treat the following as typical, not universal:

• Railroads using the General Code of Operating Rules (GCOR) commonly issue temporary speed restrictions in a track bulletin, often called a Form A, with the line number, the beginning and ending mileposts and the speed. Field flags may also mark the restricted area.
• Railroads using NORAC rules issue them in bulletin orders for planned or longer restrictions, or by a Form D for short-notice ones. FRA's own 2004 notice in Docket FRA 2001-9972 refers to "NORAC Form D or temporary speed restriction bulletin forms, advance speed signs, speed signs and resume signs" (69 FR, March 17, 2004).
• Transit agencies use their own rulebooks and general orders, under state safety oversight rather than Part 213 where the system isn't connected to the general railroad system.

The remedial action table only needs the speed and the deadline. The bulletin needs more: exact limits that cover the defect with margin, the track and rail affected, and who can cancel it. Where a field team marks the defect at milepost 112.40, the limits in the worked example run 0.10 mile either side so that the restriction covers any error in locating the spot.

Lifting it. The rule doesn't let a slow order lapse on its own. Under 213.113(a), the speed limit is the remedial action that allows operation to continue, so it stays until the rail is replaced or repaired. Before the restriction is cancelled, a designated person should confirm that the repair was completed and the track is ready for the timetable speed. After a rail change in continuous welded rail, the owner's CWR plan under 49 CFR 213.119 governs rail neutral temperature and disturbed-track procedures, and many railroads keep a short restriction on disturbed track as their own practice.

What happens when a segment can't meet its track class?

A single defective rail is handled by 213.113, but if a whole segment no longer meets its class, 213.9(b) reclassifies it to the next lower class it does meet. The rule reads, in part:

"If a segment of track does not meet all of the requirements of its intended class, it is reclassified to the next lowest class of track for which it does meet all of the requirements of this part." — 49 CFR 213.9(b)

The difference matters for slow orders. A 213.113 restriction is local: 30 mph over 0.2 mile around one defect. A 213.9(b) reclassification lowers the maximum speed for the whole segment. For example, a Class 4 freight segment (60 mph) that only meets Class 3 runs at 40 mph. Section 213.9(a) lists 213.113(a) among its exceptions, which is how a defect speed limit can apply inside a segment that otherwise keeps its class.

If a segment doesn't meet even Class 1, 213.9(b) allows operations at Class 1 speeds (10 mph freight, 15 mph passenger) for no more than 30 days, under the authority of a 213.7(a) designated person who has determined that operations may safely continue.

Behind both sits 49 CFR 213.5. An owner who knows or has notice that its track doesn't comply has three options:

A slow order is option (3) in action. The defect isn't gone; the owner is operating under a qualified person's authority and the table's conditions until it is.

How does continuous rail testing change the timeline?

Under 49 CFR 213.240, an owner using continuous rail testing is exempt from the 213.113(b) four-hour verification but must field-verify each suspect within 84 hours, or 36 hours for a suspected A, A2 or B defect. The vehicle tests without stopping, and analysts review the data afterward to produce a list of suspect locations.

Three points change the slow order process under 213.240:

• A suspect "is not considered a defect under § 213.113(c) until it has been field-verified by a person qualified under § 213.238" (213.240(e)(4)). Once verified, the owner must immediately apply the 213.113(a) remedial actions.
• A suspect not verified in time must be protected with the most restrictive remedial action for its suspected type and size, over enough track to cover the location (213.240(e)(5)). In effect, a late verification triggers a slow order automatically.
• A broken rail with separation needs immediate protection under the owner's procedures (213.240(e)(3)).

All other parts of 213.113 still apply. For the worked example, a continuous test would have given the owner up to 84 hours to field-verify the 30% fissure, because D isn't an A, A2 or B action. If it were a 30% compound fissure (action B), the window would be 36 hours.

What a slow order doesn't do

A slow order lowers the loads and the consequences of a failure, but it doesn't stop a crack from growing. Every passing wheel still loads the defect. That's why notes C and D add joint-bar deadlines and F and G add reinspection cycles.

Other limits to keep in mind:

• Sizing is an estimate. The percentage of head area comes from hand testing with ultrasonic probes, and the true size is only known when the rail is broken open. A defect sized near a band boundary (say 24% versus 26%) can move between C and D, so many owners treat a borderline result conservatively. Probe technique is covered in detecting rail defects.
• A slow order only covers what was found. Shelling and head checks can mask detail fractures from the test beam, and any stretch without a valid search is untested rail. Under 213.237(h) that untested rail needs a re-test, a 25 mph limit or replacement before the test deadline. That 25 mph is a separate rule from the 213.113 table.
• Part 213 is the minimum. Many railroads' standards are stricter, with lower speeds or faster rail changes.
• Class 6 and higher track follows 213.337, not 213.113.
• Rail transit not connected to the general railroad system is outside Part 213 and follows state safety oversight; in California that's the CPUC.
• Defects after a derailment fall under the damaged rail row (action C). Part 213 doesn't require an internal test after every derailment; see rail inspection after derailment.

Common mistakes with rail defect slow orders

How EMA Industries applies this

EMA Industries performs ultrasonic rail flaw testing for transit agencies, short lines and industrial track owners, from Southern California and mobilizing nationwide. On a slow order, what counts is how fast a verified, sized defect reaches the person who sets the remedial action. A rail flaw report should give the milepost, rail, defect type, estimated size and the matching 213.113 action, with the time the owner was notified, so the four-hour clock can be shown. To plan testing or defect verification, see our ultrasonic rail testing services or contact EMA Industries.

Related reading: 49 CFR 213.237 rail flaw detection requirements · How often must rail be tested? · FRA track safety standards (Part 213) · Compound fissure in rail

Frequently asked questions

How long can a slow order for a rail defect stay in place?

The answer depends on the remedial action. Notes H, I and B have no end date, so the speed limit lasts until the rail is replaced or repaired. Notes C and D require joint bars within 10 and 7 days, or the speed drops to 10 mph. Notes F and G require reinspection every 90 or 30 days.

Who decides whether trains can keep running over a defective rail?

A person the track owner has designated under 49 CFR 213.7 decides whether the track may continue in use (213.113(a)). For action B, and for the reduced speed under D, the person must be designated under 213.7(a) and have at least one year of supervisory experience in track maintenance.

What speed limit applies to a cracked rail?

That depends on the defect type and size. Common limits are 10 mph (A2), 30 mph (B, I, and C or D before joint bars) and 50 mph (H, and C or D after joint bars), always capped at the class maximum.

Does a broken rail always stop trains?

Not necessarily. An ordinary break takes action A or E: a designated person watches each move, or joint bars are applied per 213.121. A person qualified under 213.7(d) may authorize movement over a broken rail at no more than 10 mph while watching each movement.

What is the difference between a slow order and track reclassification?

A slow order for a defect covers a short stretch around that rail and ends with the repair. Reclassification under 213.9(b) moves a whole segment to a lower class and speed because it no longer meets the requirements of its intended class.

Sources

• 49 CFR 213.113, Defective rails, eCFR (text read on Cornell LII, October 2026)
• Track Safety Standards; Improving Rail Integrity, 79 FR 4234 (January 24, 2014), Federal Register: remedial action table and notes A–I, page 4257
• 49 CFR 213.5, Responsibility for compliance, eCFR
• 49 CFR 213.7, Designation of qualified persons, eCFR
• 49 CFR 213.9, Classes of track: operating speed limits, eCFR
• 49 CFR 213.119, Continuous welded rail (CWR) plan, eCFR
• 49 CFR 213.237, Inspection of rail, eCFR
• 49 CFR 213.240, Continuous rail testing, eCFR
• 49 CFR 213.241, Inspection records, eCFR
• 49 CFR 213.337, Defective rails (Class 6 and higher), eCFR
• FRA notice, Docket FRA 2001-9972, Northeast Corridor temporary speed restriction compliance (March 17, 2004), Federal Register via govinfo