What the story doesn’t say is how much an adult ticket is. Most family tickets are more expensive, even if only slightly, than an adult travelling on their own.
If you're travelling as a single parent with a four year old (something I did many years ago), if you have a family and friends railcard it is cheaper to use that and have the "baby" travel on a child ticket.
I have just checked this - Melksham to Llanwrda - single for 1 adult, £43.90. ... single for 1 adult + 1 child on a railcard - £37.50. .... HOWEVER - the
GWR▸ booking engine does not help me find this. It asks me how many children aged 5-15 and I have to know that a child under 5 can travel on one of these tickets. There's no box on there for me to specify number of babies to help me get the best fare.
I'm sure a manned ticket office would have helped me get the best fare!