1, the importance of a family
-This was shown when the mother always takes care of her children by reading them stories everyday. Also, the father was not a hot-tempered man.
2, hope an optimism
-Albeit the father was in jail, Bobbie gave him endless hope. She knew that her father was innocent and always see the sunny side of life. Optimism was too shown when the old gentleman had high hopes that Bobbie's father was a good fellow.
3, Act of kindness
-No matter how much the railway children and their mother grieved for the father, they without fail help others when needed. This was supported by how kind they were to Jimmy, the red shirt guy who fell in the novel. Bobbie kept him company while her siblings looked for help. The mother still nursed the injured boy when she herself was facing her own problems.
Hope this helps.