If social security and railroad retirement is only income do I need to file fed taxes

[Fern]

You may have to file a tax return if your benefits exceed the amounts listed below.

Your Social Security benefits may be taxable if your combined income (pension and social security)  exceed the amounts set forth by the IRS.  A single taxpayer with a combined income of between $25,000 and $34,000 pay income tax on up to 50 percent of their Social Security benefit. A single taxpayer with a combined income of more than $34,000 owe income tax on up to 85 percent of their Social Security payments.

Married couples filing jointly with a combined income (including both spouses) of between $32,000 and $44,000 pay tax on up to 50 percent of their benefit. Couples with a combined income of more than $44,000 pay taxes on up to 85 percent of their Social Security checks.