The YH is a relettering of the _BH_ cars, with a renumbering as well. This has led to confusion where diagrams with old codes pre 1910 are matched with new codes post 1910.
The 'H' was added to car codes to mark those suitable for traffic as peak times. Otherwise the cars remained stored. These 'H' cars do NOT indicate 'Hobsons Bay' cars, a reference to a private railway taken over in 1878. This may appear to be the case as many of these "South Suburban' cars were allocated. Moreover they reflect cars that fall into a group built prior to 1881, though there are exceptions.
One hundred and sixty four cars were recoded in 1910. The number group is part of the _Y__ group. Both form one number group 1 - 385. The YH numbers recorded by the author are:
1 - 3, 5 - 16, 18, 19, 21, 23,
25 - 29, 32, 34 - 37, 39 - 51, 53,
55 - 62, 64, 70 - 76, 78 - 88, 90, 92
97, 99, 101, 209 - 211, 214 - 216, 225 - 229
248, 249, 252, 254 - 256, 259 - 266, 268, 269
273 - 275, 280 - 287, 290 - 293, 295 - 298, 301
304, 305, 307, 308, 310 - 314, 316 - 319, 323
324, 327, 328, 331, 332, 334, 335, 338, 340
341, 345, 346, 349, 352 - 356, 359, 364, 365
367, 368, 370, 379 - 382, 384
The 'H' grouping was all done by 1902. This is to say that no more cars were down rated from Y to YH after about 1902.
Most of these cars were converted to _W__ works sleepers between 1912 and 1956. Other cars were removed and scrapped.