you do not understand, if it's a single-member LLC, then the tax laws treat it as if it doesn't exist (the reporting if property/inventory is being sold and you have a business would be on Schedule C) there's no reportable sale to your LLC and no gain or loss is recognized by you. and yes the IRS would probably object because your selling to yourself from an income tax standpoint. consider it a non-cash contribution (not charitable and not taxable) to your LLC. for the trains it's tax basis is the date of death value.
think of it this way you're moving an item from your left pocket to your right pocket.
then the question comes up is your LLC a business if not you probably have a hobby
if you have a business are the train's inventory? if inventory any income/loss on sale is ordinary
if not inventory then you're selling personal property. any gain is taxable and reported on schedule D and any losses is not deductible.
even with a multi-member LLC taxed as a partnership property can be contributed usually without any gain being recognized by the member. however, special allocations are needed when the property is sold.
here's what partnership instructions say about property contributions
Contributions to the Partnership
Generally, no gain (loss) is recognized to the partnership or any of the partners when property is contributed to the partnership in exchange for an interest in the partnership. This rule doesn't apply to any gain realized on a transfer of property to a partnership that would be treated as an investment company (within the meaning of section 351(e)) if the partnership were incorporated. If, as a result of a transfer of property to a partnership, there is a direct or indirect transfer of money or other property to the transferring partner, the partner may have to recognize gain on the exchange (in other words the partner/member is compensated for the contribution).
The basis to the partnership of property contributed by a partner is the adjusted basis in the hands of the partner at the time it was contributed, plus any gain recognized (under section 721(b)) by the partner at that time. See section 723 for more information
hobby
https://www.irs.gov/newsroom/know-the-difference-between-a-hobby-and-a-business
