I have several bags of Moondog rubber ties that are new old stock (Moondog went out of business in early 2000's). As I understand it, these are a little thicker than the Lionel metal ties so they help deaden the noise and vibration some. As you can imagine, these are difficult to find after all these years.
If you have an interest it purchasing these, please contact me using the email listed in my profile.
Good luck in your search,