Labor Employer Reporting Instructions Effective 09-18 

Appendix IV OE-1a INST

INSTRUCTIONS FOR FORM OE-1a

U.S. RAILROAD RETIREMENT BOARD

Revised 2018

The following instructions are to assist system subordinate units in (1) reporting creditable service and 

compensation and taxable earnings to their National Secretary-Treasurer or the National Reporting 

Officer of their labor organization and (2) reporting and paying retirement taxes and unemployment 

contributions. 

Form OE-1a is used to report creditable service and compensation for local units of national rail labor 

organizations covered under the Railroad Retirement Act (RRA). Local lodges, divisions, unions, and 

federations, along with district councils, should report only employees who were previously in an 

employment relation with a railroad carrier and whose earnings were $25.00 or more per month.

Form OE-1a should be sent to your National Secretary-Treasurer or National Reporting Officer within 

15 days after the end of the period covered by the report. DO NOT SEND FORM OE-1a TO THE 

RAILROAD RETIREMENT BOARD (RRB) OR TO THE INTERNAL REVENUE SERVICE (IRS).

WHERE TO GO FOR ADDITIONAL INFORMATION

• For additional forms or questions about these instructions contact either your national 

organization or a Compensation Reporting Specialist at the RRB’s Quality Reporting Service 

Center at (312) 751-4992 or email qrsc@rrb.gov.

• For questions about completing Form CT-1, tax deposit rules, or obtaining an employer 

identification number (EIN), call the IRS at 1-800-829-4933 (Business and Specialty Tax 

Line) or 1-800-829-4059 (TDD/TTY) for persons who are hearing impaired or have a speech 

disability, Monday-Friday 7 AM – 7 PM local time.

• For more information on Additional Medicare Tax, visit https://www.irs.gov/ and search for 

“Questions and Answers for the Additional Medicare Tax,” Form 8959, Additional Medicare 

Tax, and Instructions for Form 8959.

• For information on the Electronic Federal Tax Payment Systems (EFTPS) or to enroll in 

EFTPS, visit the EFTPS website at www.eftps.gov/eftps/ or call 1-800-555-4477; en español, 

1-800-244-4829; for TDD (hearing impaired) call 1-800-733-4829 from 8 AM – 8 PM (ET),

Monday-Friday. Assistance is available 24/7 unless otherwise noted. Additional information 

about EFTPS is also available in the Internal Revenue Service Publication (Pub.) 966, 

Electronic Federal Tax Payment System: A Guide to Getting Started. 

Prepared by the Quality Reporting Service Center
Labor Employer Reporting Instructions Effective 09-18

Appendix IV OE-1a INST 

A. INSTRUCTIONS FOR COMPLETING ITEMS 1-19

1. Enter the name of your national organization.

2. Enter the page number and the total number of pages included in this report. Example: Page 1 of 2.

3. (a) Enter the name and/or number of your reporting unit.

(b) Enter the Employer Identification Number (EIN) of your reporting unit.

4. Enter the RRB unit number (BA number) assigned to your type of unit. To obtain your unit number, 

contact your national organization.

5. Enter the appropriate month or quarter and year. Example: Mar 2018 or 1st Q 2018.

6. Enter the employee's last name followed by the employee’s first name and middle initial. Also, enter the 

employee's nine-digit social security number.

7. Enter the appropriate month of the quarter you are filing. Example: If you are filing for the 2nd quarter of 

2018, enter Apr in 1, May in 2, and Jun in 3.

8. Enter the gross earnings and Tier I Medicare earnings. Note: Both amounts consist of all taxable 

compensation. Please only include amounts earned for services to your unit.

9. Enter the amount of the employee Medicare tax withheld from the employee's earnings. Instructions for 

calculating the withholding amounts are in Part B of these instructions.

10. Enter the Tier I creditable retirement compensation. 

11. Enter the amount of Tier I employee tax withheld from the employee's earnings.

12. Enter the Tier II creditable retirement compensation. 

13. Enter the amount of the Tier II employee tax withheld from the employee's earnings.

14. Calculate the totals for columns 8 thru 13.

15. Enter your name and title.

16. Enter the address of your organization.

17. Enter a telephone number you may be contacted at.

18. Enter the date the report was completed.

19. Leave blank. For NRO use only.
Labor Employer Reporting Instructions Effective 09-18 

Appendix IV OE-1a INST

SAMPLE
Labor Employer Reporting Instructions Effective 09-18

Appendix IV OE-1a INST 

B. INSTRUCTIONS FOR CALCULATING WITHHOLDING AMOUNTS 

In December of each year, the RRB releases notices of the earnings maximums as well as the Tier I, Tier II, 

and Medicare tax rates for the following year. The earnings maximums and tax rates are subject to change 

annually. This information is also posted on the RRB website (https://www.rrb.gov/). 

Enter the annual compensation maximums in the corresponding boxes on the OE-1a. Compensation should not 

be taxed or reported in excess of the annual earnings maximum for an individual. Tier I taxes are not assessed 

on earnings above the Tier I annual maximum limit. Tier II taxes are not assessed on earnings above the Tier II 

annual maximum limit. There is no compensation maximum for Medicare tax.

An employee pays three payroll taxes: Tier I, Tier II, and Medicare. The employee and employer tax rates are 

the same for Tier I and Medicare but differ for Tier II. To calculate the tax withheld, multiply the taxable 

earnings by the tax rate.

The following is a calculation of Carl Carman's withholding from the sample shown in SECTION A.

MEDICARE

TAX

WITHHELD

TIER I

TAX

WITHHELD

TIER II

TAX

WITHHELD

$ 50.00 $ 50.00 $ 50.00

X 0. 0145 X 0.062 X 0.049

$ 0.73 $ 3.10 $ 2.45

NOTE: Beginning in 2013, employees pay an additional 0.9 percent Medicare tax on yearly earnings 

above $200,000. An employer is required to begin withholding Additional Medicare Tax in the pay period in 

which it pays railroad retirement (RRTA) compensation in excess of $200,000 to an employee and continue to 

withhold it each pay period until the end of the calendar year. There is no employer match for Additional 

Medicare Tax. 

The following is a calculation for the Additional Medicare Tax an employer would withhold if Pam Payroll was 

to earn over $200,000 in RRTA compensation.

In 2018, Pam Payroll earned $250,000 in RRTA compensation. $50,000 is the amount Pam Payroll earned 

over the $200,000 threshold. Her employer is required to withhold the Additional Medicare Tax on this amount.

ADDITIONAL

MEDICARE

TAX

WITHHELD

$ 50,000.00

X 0.009

$ 450.00
Labor Employer Reporting Instructions Effective 09-18 

Appendix IV OE-1a INST

C. INSTRUCTIONS FOR USE OF FORM OE-1a IN COMPLETING FORM CT-1 

Form CT-1, Employer’s Annual Railroad Retirement Tax Return, is the IRS form used to report railroad 

retirement taxes. Form CT-1 is filed annually for taxes imposed on earnings paid in a calendar year. If the 

cumulative earnings for all employees are less than the Tier II maximum, then the cumulative gross earnings 

will be equal to the cumulative Tier I and Tier II earnings.

Enter the cumulative earnings totals and withholding totals in the appropriate spaces in the TAX 

CALCULATION WORKSHEET on page two of Form OE-1a. The cumulative totals are the sums of the totals 

from all Forms OE-1a filed in the year. Enter the tax rates in Items A, B, and C on the worksheet and multiply 

by the earnings. The items from the TAX CALCULATION WORKSHEET are in the same order and directly 

correspond to items on Form CT-1. Transcribe the amounts from the worksheet to Form CT-1 using the "CT-1 

references" column on the worksheet as a guide.

The cumulative yearly totals in the following example are four times the quarterly totals from the sample 

shown in SECTION A.

FORM OE-1a TAX CALCULATION WORKSHEET

The amounts in Item A should equal Item D and amounts in Item B should equal Item E.

The items may differ a few cents due to rounding of partial cents.
Labor Employer Reporting Instructions Effective 09-18

Appendix IV OE-1a INST 

D. INSTRUCTIONS FOR USE OF FORM OE-1a IN DETERMINING TAX LIABILITY 

Taxes reported on Form CT-1 are paid monthly with two exceptions: 1) your tax liability is more than 

$100,000, in which case taxes are paid more often than monthly, or 2) your tax liability is less than $2,500, in 

which case taxes may be paid annually. All federal tax deposits must be made by electronic funds transfer. 

Generally, an electronic funds transfer is made using the Electronic Federal Tax Payment System (EFTPS). If 

you do not wish to use EFTPS, please have an authorized financial institution make the electronic deposit on 

your behalf. Taxes must be deposited with the U.S. Department of Treasury; taxes must not be paid to the 

IRS or to the RRB.

The frequency, monthly or quarterly, for filing Form OE-1a is determined by your national organization. If 

you file Form OE-1a monthly, the form can be used to calculate your monthly tax liability by completing Items 

A through H on the TAX CALCULATION WORKSHEET found on page two of Form OE-1a. If you file 

Form OE-1a quarterly, the form will not have the monthly totals needed to determine monthly tax liability. If 

you develop the monthly earnings and withholding totals, you can enter the monthly totals in the TAX 

CALCULATION WORKSHEET to calculate the monthly tax liability.

If all employees’ earnings are less than the Tier II maximum, another option for determining monthly tax 

liability is to multiply the monthly gross earnings by the combined tax rate. The combined tax rate is the sum 

of the six tax rates: Employee Medicare, Employee Tier I, Employee Tier II, Employer Medicare, Employer 

Tier I, and Employer Tier II. For example, the sum of the six tax rates for 2018 is 33.3%. If all of the 

employees’ combined earnings are less than the Tier II maximum, multiply the monthly 2018 gross earnings 

by 0.333 to obtain the monthly 2018 tax liability.
Labor Employer Reporting Instructions Effective 09-18 

Appendix IV OE-1a INST

The following example demonstrates the calculation of tax liability for March 2018 using data from the sample 

shown in SECTION A. The totals in Items A through H were developed from the figures shown for the third 

month of the first quarter.

FORM OE-1a TAX CALCULATION WORKSHEET

The amounts in Item A should equal Item D and amounts in Item B should equal Item E.

The items may differ a few cents due to rounding of partial cents.