Senior citizens can qualify for a 50% discount on Polish rail tickets if they buy a PKP Senior Citizen ID (Legitymacja Seniora). The card costs 75 z and is available to anyone over 60 (bring along a passport-sized photo). Museums will often grant senior discounts to anyone over 65. Try showing your passport or an AARP card.
For more information and resources on travel for seniors, see www.frommers.com/planning.