Nice one! There are denominations from 5 to 1.00 on tokencatalog THE COLORADO VALLEY RAILWAY CO. / PAYABLE / ON THE 1ST DAY / OF ANY MONTH / SWEETWATER / TEX. (TC-91115)
The 1979 Supplement to the Trade Tokens of Texas as published by the Token and Medal Society says, "Use of this token is not known; it is not a transportation token. The Colorado Valley Railroad was chartered in 1897 to build from Sweetwater to San Angelo; however, only seven miles of track had been laid when the road was taken over by the Kansas City, Mexico, and Orient Railway in 1900." It appears to me that they were used for payroll purposes. A crew foreman would issue them to workers based on their pay rate and hours worked, then the worker would be able to cash them in at the paymaster on the first of the month. Of course, if there were "camp followers", the worker might not have a lot left at the first of the month.
Many Texas newspapers are online - they may have more contemporary info.