Former fleet

The original Frederick City Transit bus system utilized several former Frederick County Public School buses fitted with rear exit doors. These buses were numbered 101 and 102 and painted white.

Frederick City's first new bus order consisted of 1981 vintage TMC T-30 Citycruiser thirty foot buses (a license-built version of the Ontario Bus Industries (OBI) Orion I), which served the original Red and Blue Routes and were numbered 200–203. Frederick City purchased one lone Orion I thirty foot model transit coach built in 1987 (old faithful, number 204) to serve the new White Route that ran from downtown to the city's north end.

Soon after the formation of TransIT Services of Frederick County, TransIT purchased four new Orion V, thirty foot models (numbered 322–325) in 1994 to replace the original three TMC buses. The Orion V buses wear the new green over white color scheme. Due to acceptance testing delays, TransIT operated for several weeks under a combination of the original TMC/Orion I fleet and three thirty foot Flxible Metro buses on loan from Maryland MTA. The MTA buses however were suburban models and lacked a rear exit door.

In 2001, TransIT ordered five Thomas Dennis SLF-230 low-floor buses (numbered 917–921). Service was announced and expanded before the new buses arrived due to a delivery delay from the builder. Rather than delay service for 13 months, five small front engine used Spartan/Champion "Breadboxes" (re-badged, Goshen "Transette" buses) were purchased for short term use. The breadbox buses were used for the old "FLEX" routes, which supplemented the connector routes. The low-floor Thomas buses arrived in 2002 and the breadboxes stayed in service until the last ones were sold in 2010.

Due to increase service demand, several more used Breadboxes were purchased later the same year. All of the breadboxes arrived with front entry doors and a rear wheelchair lift at the very back end of the coach. However, the first order had black banding around the windows while the second order did not.

Year	Image	Manufacturer	Model	Length (ft)	Propulsion	Fleet series	Total
1976		Superior	Pioneer 40	40'	Diesel	101–102	2
1981		Transportation Manufacturing Corporation	Citycruiser	30'	Diesel	200–203	3
1987		Orion	Orion I	30'	Diesel	204	1
1994		Orion	Orion V	30'	Diesel	322–325	4
1997		Champion Bus Incorporated	Breadbox	25'	Diesel	246–248	3
1998						872–874	3
2002		Thomas Dennis	SLF-230	30'	Diesel	917–921	5
2003		Orion	Orion V	30'	Diesel	922–928	7
2004						060–066	7

Current fleet

In 2003, TransIT purchased seven new standard Orion V models (numbers 922–928) with an additional seven delivered in 2004 (numbered 060–066). In 2005, the old Frederick City Transit—number 204 was sold, ending the era of the Frederick City Transit blue over white colors.

In March 2010, TransIT bought six new Gillig Advantage buses that have replaced the aging 300-series acquired when TransIT formed in the early 1990s. These buses have a simplified stripe which does not slope up over the windows on to the roofline at the rear of the bus.

Two additional Gillig Advantage low floor buses arrived, purchased with federal grants, the new buses sport a different paint livery and are the first hybrid buses in the system. These buses have a battery pack on the roof and use a Cummins ISB engine.

TransIT took bids in late 2013 to replace the five SLF400 buses nearing their service life. In 2015, TransIT placed an order for five re-manufactured, Gillig Advantage all-electric buses from Complete Coach Works (CCW). The new buses are numbered 779-783 and entered revenue service on June 1, 2016.

In 2018, TransIT acquired six new hybrid buses split between two deliveries of ElDorado National E-Z Rider II buses to replace older high floor buses that were removed from service due to reliability issues or accident damage. The first batch of three buses 956-958 entered service in July 2018, while the second group 122-124 entered service in October 2018.

In late 2019, TransIT began receiving four new K7M thirty-foot buses from Chinese builder BYD. The first of these buses began testing in March, before finally entering revenue service in July. As of December 2020, all four buses, 364-367 have been accepted and are now in service replacing the last few remaining Orion V buses from the 2005 order.

A temporary bus, #959, a Champion Defender, thirty-foot bus was acquired used to make up a shortfall in the roster until new buses on order arrive in mid-2021 to begin replacing the 2010 Gillig Advances buses which are now at the end of their usable service life. These buses are being retired early due to service reliability issues.^[4]

In June of 2023, TransIT Gillig Advantage bus 981 had been retired with 982-986 expected to follow suit due to state service life requirements. Six new ENC EZ-Rider II buses are expected to be delivered shortly starting with 39652. Buses are numbered according to the last three digits of Frederick County's purchase requisite number which results in a non-linear asset number.

Year	Image	Manufacturer	Model	Length (ft)	Fuel type	Fleet Series	Total
2010		Gillig	Advantage Low Floor	30'	Diesel	981–986 (981 has been retired) 982-986 being replaces as new ENC buses arrive.	5
2011			Advantage Low Floor HEV	35'	Hybrid	157-158	2
2016		Complete Coach Works/Gillig	Advantage Low Floor ZEPS	35'	Electric	779-783	5
2018		ElDorado National	E-Z Rider II	32'	Diesel	956-958	3
2018		Champion	Defender	30	Diesel	959	1
2019		ElDorado National	E-Z Rider II	32'	Diesel	122-124	3
2020		BYD	K7M	30'	Electric	364-367	4
2024		ElDorado National	E-Z Rider II	32'	Diesel	39652-39653 & 39740 (three in service)	3