There are no published plans for DSP&P MOW equipment that I have
found. However, some of the C&S folio drawings are excellent
modeling guides -- see
MOW Folios.
Here is a sample and my rough representations of them using
commercial parts.
DSP&P Wrecker # 0103 later
02510
DSP&P Rotary Snowplow
#011, later #064, C&S #01 then 92100