Solitary Confinement Reform Act This bill establishes standards for the use of solitary confinement at federal prisons. It generally limits the use of solitary confinement to situations that meet certain criteria, including confinement for the briefest term and under the least restrictive conditions practicable. It also limits the use of solitary confinement for certain categories of inmates, including pregnant women and individuals with serious mental illness. The bill requires the Bureau of Prisons (BOP) to establish a transitional process for inmates in solitary confinement, provide comprehensive mental health evaluations for inmates in solitary confinement, train employees on mental illness and the psychological effects of solitary confinement, and report annually on the use of solitary confinement. It establishes, within the BOP, an Office of the Civil Rights Ombudsman. Finally, it establishes a solitary confinement resource center within the Department of Justice's Bureau of Justice Assistance.