It ran for just under 7+1⁄2 miles (12.1 km) from Tiverton Junction station on the Bristol to Exeter line, through the Culm valley to Hemyock.

It was loss-making and underused until United Dairies built a creamery and milk products factory at Hemyock; their output became the dominant traffic.

The valley of the River Culm was an attractive, but remote and declining area in the early nineteenth century, containing the villages of Uffculme, Culmstock and Hemyock.

[1] He discussed the idea of a light railway with Henry S. Ellis, a director of the B&ER; Pain suggested a low-cost line as a steam—or possibly horse operated—tramway running in or alongside the roadway, to serve the Culm Valley settlements.

Such a line might be narrow gauge if the business was expected to be light; and by securing the enthusiasm of local people for the improvement of the district, land acquisition costs might be low.

There was some discussion about the location of the Hemyock terminus, in case extension to the London and South Western Railway (LSWR) were later required: Honiton is about ten miles away, but over challenging terrain.

The B&ER were supportive, and agreed to work the line, but they required a number of conditions that had not been expected: there must be proper station accommodation for passengers, with platforms, and for goods, with covered loading accommodation; bridges at the Turnpike road were to be of stone or brick, not timber; and a much improved track specification was required, with 15 inches of ballast.

Pain managed to persuade the Board of Trade to relax its customary dislike of level crossings, provided the train speed was limited to 16 mph.

A share prospectus was issued on 25 September 1873, stating that "The works being so unusually light, the Railway will be opened in about six months after it is commenced".

Invitations to tender for the construction were soon issued, in ten separate sections, the intention being to enable small local contractors to participate; in the event that expectation was little justified.

By September 1874, Pain was obliged to report that progress on construction had been consistently slow, and Jardine was warned that if this was not quickly accelerated, his contract would be terminated.

He needed the services of a locomotive to assist with the construction work, and one was hired in from Henry Hind & Son of Nottingham, but this proved catastrophically unreliable.

The company, and not Broome, had been paying the locomotive hire charges and it is likely that they had taken responsibility for a number of other costs not properly specified in Pain's contract arrangements.

Colonel Yolland of the Board of Trade was asked to make a formal inspection of the line with a view to opening, and he visited on 14 July.

[2] More delay was incurred, and Pain was given an ultimatum to complete by the year end; this passed and the company was borrowing increasing sums of money, now beyond the authorised limit.

However, on 20 May Yolland made another inspection, and this time he found the line ready, subject to operation on the "one engine in steam" principle, and a speed limit of 15 mph.

There was a considerable gap between the GWR's expectations and what Pain thought was reasonable, but on 27 May 1876 a special train passed up the line, depositing at the general stations stationmasters, clerks, porters and the necessary appliances for business.

In view of the apparent urgency for providing them at the time of obtaining the authorising act of Parliament, other locomotive construction had been delayed, a fact that remained a point of contention with the GWR.

Pain now complained to the GWR that the locomotives were excessively heavy; he was probably prompted to do so by damage to the track, which was exceptionally light in construction.

A number of measures were considered, including issuing additional share capital, and it was no surprise when almost no interest was shown in buying into a loss-making business.

A number of quite fantastical proposals were dreamed up, including sale to the LSWR, and using the line as the springboard for a new independent GWR route to London.

The appropriate price was low and it took some time for the shareholders to come to terms with the loss of value of their investment, but agreement was formalised on 5 August 1880, from which date the line was owned by the Great Western Railway.

Refrigeration became a practical process in the 1870s and it had the result of enabling cheap imported butter, undercutting what could be produced in home dairies.

The first train from Tiverton Junction to Hemyock, at 9.0 a.m., was allowed 65 minutes for the journey of 7½ miles, time being included for shunting sidings on the way.

A GWR report recommended closure of the passenger service and limiting the branch activity to handling goods during a single working shift, and heavily reducing facilities on the line.

However "main line" coaching stock was never used, and the imperative for this may have been the foreseen introduction of six-wheel milk tank wagons, then being trialled elsewhere on the GWR.

[2] The following Monday a 204 hp diesel locomotive operated the remaining goods traffic on the line, and was the general motive power subsequently.

The ballast is of gravel, a small proportion of sand; it was required according to the contract, to be eight inches deep under the sleepers, but is stated to average about one foot.