The rising prices of gasoline, oil and diesel fuel have claimed another victim: a start-up bus service between Cape Cod and Rhode Island.

The last run of the CapeX bus company not only represents the demise of another small-business idea in a tough economy. It also severs a small transportation link that, in time, would have tightened the bonds between the Rhode Island and Massachusetts economies and benefited people on both sides of the border.

CapeX, owned by Margaret E. Garrahan and Jay Kavanaugh, will stop service next Sunday linking Harwich, Mass., T.F. Green Airport in Warwick and the Amtrak station in Providence.

Garrahan said that in its three months of operation, the enterprise had attracted about 450 riders, but ended up losing $50,000.

“The fuel prices are killing us,” she said in an interview. “Every day it seemed to get worse and we saw no end in sight.”

The company’s two buses run on diesel fuel. The vans that supplement the buses on four trips daily used gasoline. Last week, diesel sold for an average of $4.92 a gallon and gasoline cost an average of $4.09 a gallon. When the owners planned the service last October, gas was $2.85 and diesel was $3.10 a gallon.

Garrahan said the fuel alone was costing the company $75 to $100 a trip. But what shocked her was the charge for the latest delivery of two drums of oil that the mechanics use for lubrication in the vehicle’s engines. They cost $1,100, twice what she paid six months ago.

“We debated whether to change the service, or cut it back, and decided for now there was just no way to financially make it work,” said Garrahan.

She said the number of passengers who used the service since it started in May was actually slightly ahead of the company’s business plan. They included commuters to jobs on Cape Cod, people who did business in both places, day-trippers, New Yorkers who took Amtrak to Providence and needed transportation to the Cape, and vacationers and travelers who flew into Green and who were headed for Massachusetts. There were also some military personnel returning home from active duty and players in the Cape Cod Baseball League. The CapeX service also stopped in New Bedford and Fall River. The price was $30 one way and $55 roundtrip.

The 450 passengers at the Rhode Island stops were equally split between T.F. Green and the Amtrak station.

Patti Goldstein, a spokesperson for the airport, said T.F. Green has been building a reputation as the place to land in New England, offering easy access to wherever you want to go. “Anytime you can add to the ground transportation options for a traveler is a good thing,” she said.

Garrahan said she has considered the possibility of requesting a public subsidy of some type to get the service up and running until word got out to attract more riders. She talked to representatives of the Massachusetts Executive Office of Transportation and the Cape Cod Commission and argued that other bus services, such as Plymouth and Brockton, that travel to Cape Cod had received some financial assistance. But while she said there has been support from public officials in Rhode Island and Massachusetts, she wasn’t sure how much or what step would be next if she sought a subsidy.

One advocate, Massachusetts Rep. Sarah Peake, D-Provincetown, said she would be willing to arrange a meeting between Garrahan and state transportation officials, but she said the outcome of the meeting was far from certain.

With the closing of CapeX, Garrahan said the employees and vehicles the company added for the service would be absorbed by other businesses she and Kavanaugh own, including Jay’s Equipment Repair and Cape Destinations, which provides transportation services with 35 limousines, trollies, liveries and charter buses. The company, based in Harwich, has a year-round work force of 15 and annual sales of $1.3 million

“CapeX is something we believe in,” she said, “but we have to be practical.”

CapeX is not the only bus service from Rhode Island to the Cape. Peter Pan also offers service.

But the express service CapeX offered also gave travelers another reason to stop in Rhode Island, at the train station or airport, rather than travel to Boston’s airport or train station.

The numbers of people that disembarked in Rhode Island, even if only for a short time on their way to Cape Cod, may have been small, but every bit helps make Rhode Island a place to stop, rather than just pass by.

jkostrze@projo.com