Found the answer from Amtrak site
Prohibited Items
The following kinds of items are prohibited as both checked and carry-on baggage:
Any type of gun, firearm, ammunition, explosives, or weapon.
Incendiaries, including flammable gases, liquids and fuels.
Large, sharp objects such as axes, ice picks and swords.
Corrosive or dangerous chemicals or materials, such as liquid bleach, tear gas, mace, radioactive and harmful bacteriological materials.
Batteries with acid that can spill or leak (except those batteries used in motorized wheelchairs or similar devices for mobility-impaired passengers).
Club-like items, such as billy clubs and nightsticks.
Fragile and/or valuable items, including but not limited to electronic equipment. (Laptop computers and handheld devices may be carried onboard; however, Amtrak accepts no liability for damage.)
Animals (except service animals).
Oversized and/or overweight items.
Please note: This is not an exhaustive list. Any item similar to those listed, even if not specifically mentioned here, is prohibited from being carried onboard or checked as baggage.