Adds a new subsection (j) to section 426 of the Social Security Act establishing special rules for certain 'eligible individuals' that eliminate the 24-month waiting requirement, make entitlement retroactive to the first day of the first month of entitlement, exclude application of subsection (f), and define the term 'eligible individual' including a cross-reference to Internal Revenue Code section 5000A(e)(1)(A) with an altered percentage reference.

Amends section 1811 (42 U.S.C. 1395c) by adjusting punctuation in paragraph (2) and adding a new paragraph (4) that explicitly includes 'eligible individuals (as described in section 226(j)(2))' among those eligible for the program.

Adds a new subsection (o) to section 1837 describing special enrollment period rules for individuals who become entitled to Part A pursuant to section 226(j), including when the initial enrollment period begins and a transitional rule for certain individuals tied to the date of enactment of the Stop the Wait Act of 2025.

Amends section 223 of the Social Security Act to remove the statutory waiting period for disability insurance benefits by revising subsection (a) benefit-computation language and restructuring subsection (c) (striking paragraph (2), changing the subsection heading, and redesignating subparts and internal references).

Conforming amendment to section 7(d)(3) of the Railroad Retirement Act of 1974 to update a cross-reference to Social Security Act section 223 from '223(c)(1)' to '223(c)'.