Edmonton Transit operated a small fleet of cutaway buses before the first ELF's began arriving in 1993. All of these buses featured a Ford Econoline chassis with spotting features that date them to between 1987-1991. #50 has a Goshen body, while the rest were Girardin bodied buses. The Girardin's ran with ETS until 1999, while 50 was still around into 2000, although, usually languishing behind Westwood and probably retired by then from active service. #51 managed to find a use after ETS, and ran at the City's Waste Management facility until replaced by newer buses (including an ELF, which is newer than those operated by ETS and is still running in 2017).
As an addendum, I have some data from a Fleet Allocation from 1994 which listed buses and includes some buses numbered in the standard City fleet numbering scheme, including ELF 53 (P7557). There are 3 M series fleet numbers: M2566, M2568, and M7205. Given that P is known to be about 1992/93 it's quite possible that the 3 M series numbers are 1991-92 units and became #50-52. M7205 is noteworthy as it may have been a leased unit based on that fleet number. There is also G2013 and G2014 listed which could be 48-49 although I do suspect they were the vans covered elsewhere in this section. 

Thumbnail	Bus #	Date	Body	Description
	48 and 51?	June 1997	Girardin	2 of ETS's Girardin's awaiting their next runs at Ferrier Garage. These buses were powered by propane, the last ETS buses so far to be powered by that fuel 48 or 49 maybe in the front, and 51 or 52 at the back.
	48	1999?	Girardin	#48 working a 304 at Southgate Transit Centre.
	48	1999?	Girardin	#48 working a 304 at Southgate Transit Centre.
	50	August 1998	Goshen	#50 probably on the 302 at Clareview. Pretty sure this was August 1998. I believe it was at the same time I photographed my first 1998 D40LF.
	50	September 1999	Goshen	#50 inside of Westwood Garage in
	50	2000	Goshen	#50 in the parking lot behind Westwood.
	50	2001	Goshen	ETS #50 sitting retired behind Westwood Garage
	51	2006	Girardin	#51 at the Fleet Service's Kennedale MES facility during it's time running at the Waste Management Centre, before being replaced by a second hand ELF.