Trainz

Pretty much as the title says. I own Tane and TRZ 19 I use to have a Silver Class membership but stopped it as wasn't using Trainz much. I am a casual enthusiast and pick up and put Trainz down on an ongoing basis. I like Trainz 19 and see no point in upgrading to 22 for my level of use. However I really would like to have the new HST that was remodeled by N3V. Is it available for download or purchase for use with 19? Or is it only available in 22?

Thanks