A disassembled bicycle still counts as a bicycle for NS and for bicycles you need to buy a ticket.

See https://www.ns.nl/en/travel-information/bikes-on-the-train.html

Welcome to the NS Community!

If the bike in a box or bag, it should be allowed as hand luggage, for which the (official) maximum dimensions are 85×85×85 cm.

This means a washing machine would be allowed  but in practice, they will allow smaller (floor space) luggage if it exceeds 85 cm (height) and doesn’t obstruct anything.

So, an ironing board or IKEA 60×20×160 cm high bookshelf package is no problem as long as you can store it upright against a wall near the doors.

The (obviously disassembled) bike in the photo below would not count, although I like the creativity and they will probably let you get away with it.

At your own risk, because you might be asked to leave the train or buy a € 7,50 bike ticket (allowed all day in July and August).

Welcome to the NS Community!

If the bike in a box or bag, it should be allowed as hand luggage, for which the (official) maximum dimensions are 85×85×85 cm.

This means a washing machine would be allowed  but in practice, they will allow smaller (floor space) luggage if it exceeds 85 cm (height) and doesn’t obstruct anything.

So, an ironing board or IKEA 60×20×160 cm high bookshelf package is no problem as long as you can store it upright against a wall near the doors.

The (obviously disassembled) bike in the photo below would not count, although I like the creativity and they will probably let you get away with it.

At your own risk, because you might be asked to leave the train or buy a € 7,50 bike ticket (allowed all day in July and August).

 

Warning: You need also a ticket for a bike in a box or bag and a disassembled bike. See the link in the message from @Momo