Folkestone, Sandgate and Hythe Tramways
History
The Folkestone, Sandgate and Hythe Tramway Company only operated horse trams for a very short period (from 1891 to 1893), before being taken over by one of its major shareholders, the South Eastern Railway, which itself subsequently merged with the London Chatham and Dover Railway (in 1899) to form the South Eastern and Chatham Railway Company. The latter continued to operate the horse tramway right through to its closure in 1921.
Uniforms
Although early photos of the tramway have yet to come to light, written sources suggest that staff simply wore informal attire. Uniforms were first issued following the take-over by the South Eastern Railway Company in 1893, though precisely what form these took is unclear, as photographs of the first decade of operation are rare. By the early Edwardian era however, the photographic record is much richer, clearly showing that drivers were issued with double-breasted jackets with four pairs of buttons and lapels, all edged in a lighter coloured material than the main body of the jacket; the collars bore some kind of insignia, very probably embroidered. Conductors were issued with distinctive long coats; these were single-breasted with eight buttons and upright collars. Surviving photographs are of insufficient quality to discern whether or not the collars bore insignia, though in all likelihood they did. Caps were in a military style with a tensioned crown (top), and possibly bore script-lettering grade badges, though these cannot be made out with certainty on surviving photographs. It seems unlikely that this style of cap would also have been worn in the mid-1890s, a decade when kepi-style caps were in vogue, but photographic evidence to prove this is currently lacking.
The tramway closed during the Great War, and upon re-opening, it appears to have taken a rather relaxed approach to uniforms. Although some photographs show staff wearing the pre-war uniforms, several show drivers and conductors wearing informal attire, along with a variety of overcoats, some with insignia and some without.
Unusually, and perhaps uniquely, women were employed as conductresses after the Great War and up until closure, even though they had not been set on during the war years. They were issued with piped, single-breasted jackets with lapels and long, matching skirts. Headgear took the form of a wide-brimmed bonnet turned up at one side. It is currently unclear whether these garments bore badges of any kind.
The only senior staff member was a foreman-cum-manager. In the 1920s, this individual wore a long, piped, double-breasted overcoat with lapels; the latter bore embroidered insignia. The cap, which was military in style at this time, bore a large round cap badge, probably an SECR issue of embroidered cloth.
Further reading
For a history of the system, see: 'The Hythe and Sandgate Railway, Incorporating the Hythe and Sandgate Tramway' by Brian Hart; Wild Swan Publications (1987).
Images
Horse tram drivers and conductors
An unidentified covered toastrack car waits in the passing loop on Princes Parade — photo undated, but from the fashions on display, possibly late Victorian or early Edwardian. With thanks to the National Tramway Museum. 
A blow-up of the above photo showing the driver, who is wearing a smart, double-breasted jacket edged in a lighter material than the main body, and with lapels; the latter clearly carry insignia of some description. His cap is military in style with a tensioned crown (top), but whether it carried a badge or not is impossible to say.
Another blow-up of the above photo, this time of the conductor, who is wearing a long single-breasted coat with eight buttons and upright collars; unfortunately, the resolution is not sufficient to discern whether the collars or the cap bear badges of any description.
Toastrack No 5 standing outside the depot at Hythe with a queue of passengers — photo undated, but from the fashions, probably Edwardian. Both men are wearing the same smart style of uniform as seen in the previous photo. With thanks to the National Tramway Museum. 
A fully laden toastrack car (No 3) standing in Princes Parade — photo purportedly taken in 1910. The driver and conductor are wearing the same style of uniform seen in previous photographs. Photo courtesy of the Tramways and Light Railway Society, with thanks to David Voice.
Horsecar No 5 stands at the Red Lion terminus (Hythe) in 1912. Photo courtesy of the Tramways and Light Railway Society, with thanks to David Voice.
A blow-up of the above photo showing the driver, James Pilcher, who is wearing a heavy-duty coachman's or greatcoat (with collar insignia); his military-style cap would appear to bear a long badge, possibly a script-lettering grade badge, though this could equally well be a reflection off the chin strap, which was worn above the peak.
Another shot taken from the same photo, this time showing the conductor, who is wearing the standard single-breasted coat with upright collars; his cap also appears to bear a cap badge, though once again, this may be a trick of the light reflecting on the chin strap.
Toastrack No 5 outside Hythe depot — date unknown, but possibly taken around the time of the Great War. Photo courtesy of the Tramways and Light Railway Society, with thanks to David Voice.
A rather proprietorial conductor with Horsecar No 5 in Red Lion Square at the Hythe terminus — photo undated, but probably taken after the Great War. Photo courtesy of the Tramways and Light Railway Society, with thanks to David Voice.
A blow-up of the above photo showing the conductor, who is wearing a rather anachronistic looking frock-style coat and bow tie.
The driver of covered, cross-bench car No 1 encourages his charges outside the Royal Oak pub at the bottom of Sandgate Hill. Although the photo is undated, it certainly post-dates the Great War, as No 1 was only rebuilt into this form in 1919. Photo courtesy of the Tramways and Light Railway Society, with thanks to David Voice.
A blow-up of the above photo showing the driver, who appears to have a script-lettering grade badge — 'Driver' — on his cap, though this is far from certain.
An unidentified horsecar (probably No 5), clearly marked 'SE&CR', standing outside the Red Lion terminus at Hythe — photo undated, though in view of the large baggy caps, almost certainly taken after the Great War when these became very fashionable. The individual in uniform is purportedly Conductor Harry Jago, whose cap appears to bear a large round cap badge. The only other photograph of an individual wearing a similar badge is of James Pilcher, who was the SECR foreman-in-charge; he effectively managed the company's trams and the omnibuses, as well as its nearby town office. Photo courtesy of the Tramways and Light Railway Society, with thanks to David Voice.
Driver and conductor (Richard Jago; brother of Harry Jago), both in informal attire, pose for the camera outside the Imperial Hotel on Princes Parade — photo dated 1921. Photo courtesy of the Tramways and Light Railway Society, with thanks to David Voice.