I have various 4 axel diesels. There are GP9's, GP35's, GP38's and GP40's from Athearn, Atlas, Bachmann and Walthers.
When I started modeling in HO DCC was not even a consideration so most of my early collection was straight DC. The Atlas GP38's where my first DCC locos even though I had no access to a DCC system. When the club I belonged to add DCC I started to convert other units to DCC mainly my new SD70mac's.
Just like with the pro-type railroad I will be shedding most of the smaller Motive Powers like the GP9's and GP40's they will be replaced with new SD70mac's. I will keep the two GP38 because they already have DCC. The Bachmann units defiantly are shedded. These units are under powered add are just not needed.
Information to consider: At a past show I had a chance to run my Athearn SD70Mac's and an Atlas GP38 unit. But because I belonged to a modular club and they have modules of varying wear and age none of the larger mac's would make a complete circuit around the display successfully. Well it’s a good thing I bring all of my motive power because the only units that could get the job done where the GP9’s. So I guess I won't be shedding the 9's any time soon. Besides a good railroad needs a good mix of motive power.
1802 is a Walthers GP9 this is a DC unit.
1806 is a Walthers GP9 this is a DC unit.
2003 is an Atlas GP38 it is DC/DCC selectable.
2005 is an Atlas GP38 it is DC/DCC selectable.
2501 is an Athearn GP35
2502 is an Athearn GP40 I bought already custom painted, It is DC
2503 is an Athearn GP35
2504 is an Athearn GP40 it is custom painted in blue and yellow. It is DC.
3003 is a Bachmann GP40-2 custom painted. It is DC.
3009 is an Athearn GP40-2
3010 is an Athearn GP40-2
3012 is a Bachmann unit it is DC.
3014 is an Atheran GP40 It was super detailed when I bought it. It is DC.
3015 is a Bachmann GP40-2 I have a couple of these they came with the McKinley Explorer train sets. I no longer run these.