Railroad W-2 Box 14 Codes: Tier 1, Tier 2, and Excess Refunds

If you work for a railroad, Box 14 of your W-2 is where your Railroad Retirement Tax Act (RRTA) withholding lives, and the railroad W-2 Box 14 codes almost always break down into five items: RRTA compensation, Tier 1 tax, Tier 2 tax, Medicare tax, and (if you earned enough) Additional Medicare Tax. Boxes 3 through 6 stay blank because RRTA replaces Social Security and Medicare for railroad employees, so every retirement-related figure your employer withheld gets pushed into Box 14 under abbreviated labels the IRS does not standardize.¹

Why Boxes 3 Through 6 Are Empty

A standard W-2 reports Social Security wages and tax in Boxes 3 and 4 and Medicare wages and tax in Boxes 5 and 6. Railroad employers do not use those boxes at all. Because RRTA is a separate federal system from FICA, the IRS tells railroad employers to leave Boxes 3 through 6 blank and report everything under Box 14 instead.¹

So if you look at your form and see zeros or blanks where you expect Social Security and Medicare numbers, nothing is wrong. That empty space is the signal that the real tax information is sitting in Box 14 under labels your payroll department picked.

What Each Box 14 Code Means

The IRS requires railroad employers to label each Box 14 item as RRTA compensation, Tier 1 tax, Tier 2 tax, Medicare tax, or Additional Medicare Tax, but each employer uses its own shorthand.² The common abbreviations:

RRTA Comp, RR Comp, Tier 1 Comp: Total compensation subject to RRTA taxes. This is a wage figure, not a tax amount, and it usually tracks closely with Box 1.
T1, Tier 1 Tax, T1T, RRTA-T1: The 6.2% Tier 1 retirement tax withheld during the year. This is the railroad equivalent of what would otherwise appear in Box 4.
T2, Tier 2 Tax, T2T, RRTA-T2: The 4.9% Tier 2 supplemental pension tax withheld. There is no FICA counterpart.
Med, Medicare, RRTA Med: The 1.45% Medicare tax withheld. Functionally identical to FICA Medicare.
Add Med Tax, Addl Medicare, RRTA Add Med: The 0.9% Additional Medicare Tax withheld on compensation above $200,000 in the calendar year.³
T1W, RRTA1: Wages subject to Tier 1 tax (the wage base, not the tax).
T2W, RRTA2: Wages subject to Tier 2 tax. Because the Tier 2 cap is lower, this number is smaller than T1W for higher earners.
GTL, Group Term Life: The taxable cost of employer-provided group term life insurance over $50,000, reported in Box 14a in addition to Box 12 Code C.²

If a label on your W-2 does not match any of the above, call payroll before you file. Guessing wrong can throw off the excess-withholding math or wipe out a Tier 2 refund you are owed.

2026 Rates and Wage Bases to Check Against

The dollar amounts in Box 14 should line up with current RRTA rates and caps. For 2026:

Tier 1 retirement, 6.2%: Applies to the first $184,500 of compensation, the same cap as Social Security. Maximum employee tax: $11,439.⁴
Tier 1 Medicare, 1.45%: No wage cap. Applies to every dollar.⁵
Tier 2, 4.9%: Applies to the first $137,100 of compensation. Maximum employee tax: $6,717.90.⁵
Additional Medicare, 0.9%: Withheld once RRTA compensation crosses $200,000 in the year.

A quick sanity check: multiply your Tier 1 wage figure by 6.2% and compare to the Tier 1 tax amount; do the same for Tier 2 at 4.9% and Medicare at 1.45%. Small rounding differences are normal; larger gaps are worth a call to payroll.

Entering Box 14 Codes in Tax Software

Mainstream tax programs like TurboTax, H&R Block, and FreeTaxUSA were built around standard FICA W-2s, so Box 14 entries for railroad workers require manual category selection. The workflow is the same across most products: for each line in Box 14, type the label your employer used, enter the dollar amount, then pick the matching category from the dropdown. The railroad categories (Railroad Retirement Tier 1 Tax, Tier 2 Tax, Medicare Tax, Additional Medicare Tax, and Compensation) usually sit near the bottom of a long alphabetical list.

Two mistakes cause most of the problems. Do not put your Tier 1 tax in Box 4; Box 4 should stay empty on screen just as it is on paper, because the excess-withholding credit depends on the software seeing Tier 1 come through Box 14 with the correct category. And enter total RRTA compensation as its own Box 14 line categorized as railroad retirement compensation, since some programs use that figure to decide whether excess tax was withheld. Skipping it can trigger a false alert or hide a real refund.

Recovering Excess Tier 1 or Tier 2 Withholding

If you worked for two or more employers in 2026, each one withheld as if it were your only job, and your combined withholding can run past the annual caps. How you get the money back depends on which tier is involved.

Excess Tier 1: Schedule 3 Credit

Excess Tier 1 retirement tax from multiple employers is claimed as a refundable credit on Schedule 3, Line 11, which flows to your Form 1040 and either lowers what you owe or increases your refund.⁶ Add up all Tier 1 retirement tax across every W-2, subtract $11,439, and the difference is your credit. Tax software does this automatically if the Box 14 categories were set correctly.

The credit only works when more than one employer caused the overpayment. If a single employer withheld too much on its own, you have to go back to that employer for a corrected W-2 and a refund of the excess.⁷

Excess Tier 2: Form 843

Tier 2 overpayments do not go on Form 1040 or Schedule 3, even with multiple employers. You claim them by filing Form 843, Claim for Refund and Request for Abatement, directly with the IRS.⁷ If combined Tier 2 withholding exceeds $6,717.90 for 2026, the excess is refundable. On the form, check box “a” on Line 4 for employment tax, write “Excess tier 2 RRTA” on Line 8, show your computation, and attach copies of every W-2 for the year.⁸

If One Employer Over-Withheld

Single-employer over-withholding of either tier cannot be fixed on your return. Ask the employer to correct it first. If they refuse or fail to act, file Form 843 with a statement from the employer about any portion already reimbursed. No statement available? Attach your own written explanation along with your W-2s.⁸

Deadline

You have three years from the date you filed your original return, or two years from the date you paid the tax, whichever is later, to submit Form 843. After that, the refund is gone.⁸

Additional Medicare Tax Thresholds

The 0.9% Additional Medicare Tax reported in Box 14 kicks in at these thresholds based on filing status:⁹

Single or head of household: $200,000
Married filing jointly: $250,000
Married filing separately: $125,000

Your employer must start withholding once RRTA compensation passes $200,000 in the year, regardless of your actual filing status. If you file jointly, your real threshold is $250,000, so you may get some withheld tax back when you reconcile on your return.³ For railroad workers, RRTA compensation is compared to the threshold separately from any non-railroad wages or self-employment income before the categories are combined on the return.

Sickness and Disability Codes

Some railroad W-2s show a Box 14 entry tied to benefits paid under the Railroad Unemployment Insurance Act. Sickness benefits are excluded from Tier 1 taxes to the extent they qualify, and the Box 14 code typically shows the amount of sickness pay excluded from RRTA withholding.¹⁰ If one of these codes appears on your form, factor it in when you reconcile wage totals against tax withheld, because it affects how much of your pay was actually subject to Tier 1.

1
Railroad Retirement Board. Chapter 05 Form W-2, Wage and Tax Statement and Form W-3, Transmittal of Wage and Tax Statements
2
Internal Revenue Service. 2026 General Instructions for Forms W-2 and W-3
3
Internal Revenue Service. Questions and Answers for the Additional Medicare Tax
4
Social Security Administration. Contribution and Benefit Base
5
Railroad Retirement Board. Railroad Retirement and Unemployment Insurance Taxes in 2026
6
Internal Revenue Service. 2025 Schedule 3 (Form 1040) – Additional Credits and Payments
7
Internal Revenue Service. Topic No. 608, Excess Social Security and RRTA Tax Withheld
8
Internal Revenue Service. Instructions for Form 843 (12/2024)
9
Internal Revenue Service. Topic No. 560, Additional Medicare Tax
10
Internal Revenue Service. Railroad Retirement Tax Act (RRTA) Desk Guide (January 2009)